Author Archives: Priyanka

In This Post we are  providing Chapter-4 Chemical Kinetics NCERT MCQ for Class 12 Chemistry which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON CHEMISTRY KINECTICS

Question 1.
A first order reaction has a half life period of 34.65 seconds. Its rate constant is
(a) 2 × 10^-2 s^-1
(b) 4 × 10^-4 s^-1
(c) 20 s^-1
(d) 2 × 10^-4 s^-1

Answer: (a) 2 × 10^-2 s^-1

Question 2.
If a graph is plotted between In k and 1/T for the first order reaction, the slope of the straight line so obtained is given by
(a) –EaR
(b) Ea2.303R
(c) 2.303Ea.R
(d) Ea2.303

Answer: (a) –EaR

Question 3.
The unit of rate constant for a zero order reaction is
(a) mol L^-1s^-1
(b) s^-1
(c) L mol^-1s^-1
(d) L²mol^-2s^-1

Answer: (a) mol L^-1s^-1

Question 4.
A catalyst increases the speed of a chemical reaction by
(a) increasing activation energy
(b) decreasing activation energy
(c) increasing reactant energy
(d) decreasing threshold energy

Answer: (b) decreasing activation energy

Question 5.
The units of the rate constant for the second order reaction are:
(a) mol^-1 litre s^-1
(b) mol litre^-2 s^-1
(c) s^-1
(d) mol litre^-1 s^-1

Answer: (a) mol^-1 litre s^-1

Question 6.
The value of k for a reaction is 2.96 × 10^-30 s^-1. What is the order of the reaction?
(a) Zero
(b) 3
(c) 2
(d) 1

Answer: (d) 1

Question 7.
A reaction is found to be of second order with respect to concentration of carbon monoxide. If concentration of carbon monoxide is doubled, the rate of reaction will
(a) triple
(b) increase by a factor of 4
(c) double
(d) remain unchanged

Answer: (b) increase by a factor of 4

Question 8.
If the concentrations are expressed in mol litre^-1 and time in s, then the units of rate constant for the first-order reactions are
(a) mol litre^-1 s^-1
(b) mol^-1 litre s^-1
(c) s^-1
(d) mol² litre^-2 s^-1

Answer: (c) s^-1

Question 9.
The half life of a first order reaction having rate constant 200 s^-1 is
(a) 3.465 × 10^-2 s
(b) 3.465 × 10^-3 s
(c) 1.150 × 10^-2 S
(d) 1.150 × 10^-3 S

Answer: (b) 3.465 × 10^-3 s

Question 10.
The rate of a reaction is 1.209 × 10^-4L² mol^-2s^-1. The order of the reaction is:
(a) zero
(b) first
(c) second
(d) third

Answer: (d) third

Question 11.
A catalyst increases the rate of a reaction by
(a) increasing threshold energy
(b) increasing activation energy
(c) activating the reactants
(d) lowering activation energy

Answer: (d) lowering activation energy

Question 12.
Time required for 100% completion of a zero order reaction is:
(a) t_100% = a/k
(b) t_100% = a.k
(c) t_100% = a/2k
(d) None of these

Answer: (a) t_100% = a/k

Question 13.
Arrhenius equation is represented by:
(a) k = Ae^Ea/RT
(b) k = Ae^-Ea/RT
(c) t1/2 = 0.693/k
(d) None of these

Answer: (b) k = Ae^-Ea/RT

Question 14.
The overall order of a reaction, which has the rate expression: Rate = AC[A]^1/2[B]^3/2 is:
(a) First order
(b) Second order
(c) Third order
(d) Zero order

Answer: (b) Second order

Question 15.
If half life period of a first order reaction is 100 seconds. Then rate constant will be:
(a) 6.93 × 10^-3 second^-1
(b) 6.93 × 10^-2 second^-1
(c) 0.693 second^-1
(d) 6.93 second^-1

Answer: (a) 6.93 × 10^-3 second^-1

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In This Post we are  providing Chapter-3 Electrochemistry NCERT MCQ for Class 12 Chemistry which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON ELECTROCHEMISTRY

Question 1.
If 96500 coulomb electricity is passed through CuSO₄ solution, it will liberate
(a) 63.5 gm of Cu
(b) 31.76 gm of Cu
(c) 96500 gm of Cu
(d) 100 gm of Cu

Answer: (b) 31.76 gm of Cu

Question 2.
Fused NaCl on electrolysis gives ………….. on cathode.
(a) Chlorine
(b) Sodium
(c) Sodium amalgam

Answer: (b) Sodium

Question 3.
The standard electrode potentials for the half cell reactions are:
Zn → Zn^2-– 2e^– E° = 0.76 V
Fe → Fe^2- + 2^– E° = -0.41 V
The emf of the cell reaction
Fe^2- + Zn → Zn^2- + Fe is
(a) -0.35 V
(b) +0.35 V
(c) -1.17 V
(d) +1.17 V

Answer: (b) +0.35 V

Question 4.
Which of the following is a secondary cell?
(a) Leclanche cell
(b) Lead storage battery
(c) Concentration cell
(d) All of these

Answer: (b) Lead storage battery

Question 5.
For a certain redox reaction, E° is positive. This means that
(a) ΔG° is positive, K is greater than 1
(b) ΔG° is positive, K is less than 1
(c) ΔG° is negative, K is greater than 1
(d) ΔG° is negative, K is less than 1Answer

Answer: (c) ΔG° is negative, K is greater than 1

Question 6.
Cell reaction is spontaneous, when
(a) E0red is negative
(b) ΔG° is negative
(c) E0oxid is Positive
(d) ΔG° is positive

Answer: (b) ΔG° is negative

Question 7.
Equilibrium constant K is related to E0cell and not E_cell because
(a) E0cell is easier to measure than E_cell
(b) E_cell becomes zero at equilibrium point but E0cell remains constant under all conditions
(c) at a given temperature, E_cell changes hence value of K can’t be measured
(d) any of the terms E_cell or E0cell can be used

Answer: (b) E_cell becomes zero at equilibrium point but E0cell remains constant under all conditions

Question 8.
Molar conductivity of 0.15 M solution of KCl at 298 K, if its conductivity of 0.0152 S cm^-1 w ill be
(a) 124 Ω^-1 cm² mol^-1
(b) 204 Ω^-1 cm² mol^-1
(c) 101 Ω^-1 cm² mol^-1
(d) 300 Ω^-1 cm² mol^-1

Answer: (c) 101 Ω^-1 cm² mol^-1

Question 9.
Electrical conductance through metals is called metallic or electronic conductance and is due to the movement of electrons. The electronic conductance depends on
(a) the nature and structure of the metal
(b) the number of valence electrons per atom
(c) change in temperature
(d) all of these

Answer: (d) all of these

Question 10.
The specific conductivity of N/10 KCl solution at 20°C is 0.0212 ohm^-1 cm^-1 and the resistance of the cell containing this solution at 20°C is 55 ohm. The cell constant is
(a) 3.324 cm^-1
(b) 1.166 cm^-1
(c) 2.372 cm^-1
(d) 3.682 cm^-1

Answer: (b) 1.166 cm^-1

Question 11.
Faraday’s law of electrolysis is related to
(a) Atomic number of cation
(b) Speed of cation
(c) Speed of anion
(d) Equivalent weight of electrolyte

Answer: (d) Equivalent weight of electrolyte

Question 12.
The molar conductivity is maximum for the solution of concentration
(a) 0.004 M
(b) 0.002 M
(c) 0.005 M
(d) 0.001 M

Answer: (d) 0.001 M

Question 13.
Units of the properties measured are given below. Which of the properties has been not matched correctly?
(a) Molar conductance = Sm² mol^-1
(b) Cell constant = m^-1
(c) Specific conductance of = S m²
(d) Equivalence conductance = S m² (g eq)^-1

Answer: (c) Specific conductance of = S m²

Question 14.
How long would it take to deposit 50 g of Al from an electrolytic cell containing Al₂O₃ using a current of 105 ampere?
(a) 1.54 h
(b) 1.42 h
(c) 1.32 h
(d) 2.15 h

Answer: (b) 1.42 h

Question 15.
The charge required for reducing 1 mole of MnO−4 to Mn^2- is
(a) 1.93 × 10⁵ C
(b) 2.895 × 10⁵ C
(c) 4.28 × 10⁵ C
(d) 4.825 × 10⁵ C

Answer: (d) 4.825 × 10⁵ C

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In This Post we are  providing Chapter-2 Solutions Class NCERT MCQ for Class 12 Chemistry which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON SOLUTIONS CLASS

Question 1 : An aqueous solution of hydrochloric acid

a) Obeys Raoult’s law
b) Shows negative deviation from Raoult’s law
c) Shows positive deviation from Raoult’s law
d) Obeys Henry’s law at all compositions

Answer : B

Question 2 :12g of urea is dissolved in 1 liter of water and 68.4 g of sucrose is dissolved in 1 liter of water. The lowering of vapor pressure of first case is

a) equal to second
b) greater than second
c) less than second
d) double that of second

Answer : A

Question 3 : At a particular temperature, the vapor pressures of two liquids A and B are respectively 120 and 180 mm of mercury. If 2 moles of A and 3 moles of B are mixed to form an ideal solution, the vapor pressure of the solution at the same temperature will be (in mm of mercury)

a) 156

b) 145
c) 150

d) 108

Answer : A

Question 4 : The freezing point of equimolar aqueous solution will be highest for

a) C₆H₅NH₃ ⁺Cl^–   b) Ca(NO₃)₂
c) La(NO₃)₂         d) C₆H₁₂O₆

Answer : D

Question 5: Which of the following 0.10 m aqueous solutions will have the lowest freezing point ?

a) Al₂(SO₄)₃

 b) C₆H₁₂O₆
c) KCl  

d) C₁₂H₂₂O₁₁

Answer : A

Question 6 : A solution containing 10g per dm³ of urea (molecular mass = 60 gmol^–1) is isotonic with a 5% solution of a non volatile solute. The molecular mass of this non volatile solute is

a) 300 g mol^–1

 b) 350 g mol^–1
c) 200 g mol^–1

 b) 250 g mol^–1

Answer : A 

Question 7: The vapor pressure of a solvent decreases by 10 mm of Hg when a non-volatile solute was added to the solvent. The mole fraction of the solute in the solution is 0.2. What should be the mole fraction of the solvent if the decrease in
the vapor pressure is to be 20 mm of Hg ?

a) 0.8

b) 0.6
c) 0.4

d) 0.2

Answer : B

Question 8 : A solution containing 1.8 g of a compound (empirical formula CH₂O) in 40 g of water is observed to freeze at –0.465° C. The molecular formula of the compound is (K_f of water = 1.86 kg K mol^–1)

a) C₂H₄O₂ 

b) C₃H₆O₃
c) C₄H₈O₄ 

d) C₆H₁₂O₆

Answer : D

Question 9 : Which observation(s) reflect(s) colligative properties?
(i) A 0.5 m NaBr solution has a higher vapor pressure than a 0.5 m BaCl₂ solution at the same temperature
(ii) Pure water freezes at the higher temperature than pure methanol
(iii) a 0.1 m NaOH solution freezes at a lower temperature than pure water

Choose the correct answer from the codes given below

a) (i), (ii) and (iii) b) (i) and (ii)
c) (ii) and (iii)       d) (i) and (iii)

Answer : D

Question 10 : The vapor pressure of benzene at 30°C is 121.8 mm. By adding 15 g of non-volatile solute in 250 g of benzene, its vapor pressure is decreased to 120.2 mm. The molecular weight of solute is :

a) 156.6 g

b) 267.4 g
c) 356.3 g

d) 467.4 g

Answer : C

Question 11: Pure benzene freezes at 5.45°C. A 0.374 m solution of tetrachloroethane in benzene freezes at 3.55°C. The Kf for benzene is:

a) 0.508

b) 5.08
c) 50.8  

d) 508

Answer : B

Question 12 : 0.450 g of urea (mol.wt.60) in 22.5 g of water show 0.170°C of elevation in boiling point. The molal elevation constant of water is:

a) 0.051°C

b) 0.51°C
c) 5.1°C  

d) 0.83°C

Answer : B

Question 13 : The colligative property is not represented by :

a) elevation in boiling point
b) osmotic pressure
c) optical activity
d) relative lowering of vapour pressure

Answer : C

Question 14 : 20 g of a substance were dissolved in 500 mL of water and the osmotic pressure of the solution was found to be 600 mm of mercury at 15°C. The molecular weight of substance is :

a) 998 

b) 1028
c) 1098

d) 1198

Answer : D

Question 15 : Which one of the statements given below concerning properties of solutions, describes a colligative effect?

a) Boiling point of pure water decreases by the addition of ethanol
b) Vapour pressure of pure water decreases by the addition of nitric acid
c) Vapour pressure of pure benzene decreases by the addition of naphthalene
d) Boiling point of pure benzene increases by the addition of toluene

Answer : C

In This Post we are  providing Chapter-1 The Solid State NCERT MCQ for Class 12 Chemistry which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON THE SOLID STATE

Question 1.
Which one of the following is non-crystalline or amorphous?
(a) Diamond
(b) Graphite
(c) Glass
(d) Common Salt

Answer: (c) Glass

Question 2.
NaCl type crystal (with coordination no. 6 : 6) can be converted into CsCl type crystal (with coordination no. 8 : 8) by applying
(a) high temperature
(b) high pressure
(c) high temperature and high pressure
(d) low temperature and low pressure

Answer: (b) high pressure

Question 3.
How many chloride ions are surrounding sodium ion in sodium chloride crystal ?
(a) 4
(b) 8
(c) 6
(d) 12

Answer: (c) 6

Question 4.
In NaCl structure
(a) all octahedral and tetrahedral sites are occupied
(b) only octahedral sites are occupied
(c) only tetrahedral sites are occupied
(d) neither octahedral nor tetrahedral sites are occupied

Answer: (b) only octahedral sites are occupied

Question 5.
In Zinc blende structure
(a) zinc ions occupy half of the tetrahedral sites
(b) each Zn^2- ion is surrounded by six sulphide ions
(c) each S^2- ion is surrounded by six Zn²⁺ ions
(d) it has fee structure

Answer: (c) each S^2- ion is surrounded by six Zn²⁺ ions

Question 6.
A unit cell of BaCl₂ (fluorite structure) is made up of
(a) four Ba²⁺ ions and four Cl^– ions
(b) four Ba^2- ions and eight Cl^– ions
(c) eight Ba² ions and four Cl^– ions
(d) four Ba² ions and six Cl^– ions

Answer: (b) four Ba^2- ions and eight Cl^– ions

Question 7.
Alkali halides do not show Frenkel defect because
(a) cations and anions have almost equal size
(b) there is a large difference in size of cations and anions
(c) cations and anions have low coordination number
(d) anions cannot be accommodated in voids

Answer: (a) cations and anions have almost equal size

Question 8.
The coordination number of Y will be in the XY types of crystal:
(a) 6
(b) 8
(c) 12
(d) 4

Answer: (a) 6

Question 9.
The fraction of the total volume occupied by the atoms present in a simple cube is
(a) π/4
(b) π/6
(c) π/3√2
(d) π/4√2

Answer: (b) π6

Question 10.
Edge length of unit cell of chromium metal is 287 pm with bcc arrangement. The atomic radius is of the order
(a) 287 pm
(b) 574 pm
(c) 124.27 pm
(d) 143.5 pm

Answer: (c) 124.27 pm

Question 11.
The edge length of fee cell is 508 pm. If radius of cation is 110 pm, the radius of anion is
(a) 110 pm
(b) 220 pm
(c) 285 pm
(d) 144 pm

Answer: (d) 144 pm

Question 12.
The density of a metal which crystallizes in bcc lattice with unit cell edge length 300 pm and molar mass 50 g mol^-1 will be
(a) 10 g cm^-3
(b) 14.2 g cm^-3
(c) 6.15 g cm^-3
(d) 9.3 2 g cm^-3

Answer: (c) 6.15 g cm^-3

Question 13.
How many lithium atoms are present in a unit cell with edge length 3.5 Å and density 0.53 g cm^-3? (Atomic mass of Li = 6.94):
(a) 2
(b) 1
(c) 4
(d) 6

Answer: (a) 2

Question 14.
The distance between Na^– and CL^– ions in NaCl with a density 2.165 g cm^-3 is
(a) 564 pm
(b) 282 pm
(c) 234 pm
(d) 538 pm

Answer: (b) 282 pm

Question 15.
An element with atomic mass 100 has a bcc structure and edge length 400 pm. The density of element is
(a) 10.37 g cm^-3
(b) 5.19 g cm^-3
(c) 7.29 g cm^-3
(d) 2.14 g cm^-3

Answer: (b) 5.19 g cm^-3

In This Post we are  providing Chapter-15 Communication System NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON COMMUNICATION SYSTEM

Question 1.
Who undertook the first space walk and in which year?
(a) Leonov 1965
(b) Neil Armstrong, 1969
(c) Rakesh Sharma. 1998
(d) None of these

Answer: (a) Leonov 1965

Question 2.
The term used “to collect the information about an object and a place without physical contact” is called :
(a) modulation
(b) communication
(c) amplification
(d) remote sensing

Answer: (d) remote sensing

Question 3.
The velocity of electromagnetic wave is:
(a) 3 × 10⁵ ms^-1
(b) 3 × 10⁶ ms^-1
(c) 3 × 10⁸ ms^-1
(d) 3 × 10¹⁰ ms^-1

Answer: (c) 3 × 10⁸ ms^-1

Question 4.
The audio frequencies range from:
(a) 20 Hz to 20.000 kHz
(b) 20 Hz to 20 kHz
(c) 20 kHz to 20.000 kHz
(d) None of these

Answer: (b) 20 Hz to 20 kHz

Question 5.
The wavelength of a wave of frequency 10 kHz is:
(a) 30 m
(b) 300 m
(c) 30 km
(d) 300 km

Answer: (c) 30 km

Question 6.
The area served by an antenna of height 100 m is:
(a) 10⁹m²
(b) 4 × 10⁹ m²
(c) 6 × 10⁹m²
(d) 8 × 10¹⁰m²

Answer: (b) 4 × 10⁹ m²

Question 7.
Which of the following is not transducer?
(a) Loudspeaker
(b) Amplifier
(c) Microphone
(d) All

Answer: (b) Amplifier

Question 8.
The space waves which are affected seriously by atmospheric conditions are:
(a) MF
(b) HUF
(c) VHF
(d) UHF

Answer: (d) UHF

Question 9.
An antenna is:
(a) Inductive
(b) Capacitive
(c) Resistive
(d) A transformer

Answer: (a) Inductive

Question 10.
Broadcasting antenna are generally:
(a) Omni directional type
(b) Vertical type
(c) Horizontal type
(d) None

Answer: (b) Vertical type

Question 11.
The modulation index in amplitude modulation is:
(a) Always zero
(b) Between 0 and 1
(c) Between 1 and ∞
(d) None of these

Answer: (c) Between 1 and ∞

Question 12.
The output of a digital computer is an example of:
(a) digital signal
(b) analog signal
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer: (a) digital signal

Question 13.
Name the man who was first to place his foot on the moon and in which year:
(a) Neil Armstrong, 1969
(b) James Van A lien, 1971
(c) Leonov, 1965
(d) None of these

Answer: (a) Neil Armstrong, 1969

Question 14.
A microphone converts:
(a) sound signals into electrical signals
(b) electrical signals into sound signals
(c) both (a) and (b)
(d) Neither (a) nor (b)

Answer: (a) sound signals into electrical signals

Question 15.
A loudspeaker converts:
(a) electrical signals into sound signals
(b) sound signals into electrical signals
(c) both (a) and (b)
(d) neither (a) nor (b)

Answer: (a) electrical signals into sound signals

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In This Post we are  providing Chapter-14 Semiconductor Electronic : Material, Devices and Simple Circuits NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON SEMICONDUCTOR ELECTRONIC: MATERIAL, DEVICES AND SIMPLE CIRCUITS

Q.1. In a semiconductor
(a) there are no free electrons at 0 K
(b) there are no free electrons at any temperature
(c) the number of free electrons increases with pressure
(d) the number of free electrons is more than that in a conductor.

Answer: (a)

Q.2. Let n_h and n_e be the number of holes and conduction electrons in an extrinsic semiconductor. Then
(a) n_h > n_e

 (b) n_h = n_e 

(c) n_h < n_e 

(d) n_h ≠ n_e

Answer: (d)

Q.3. A p-type semiconductor is
(a) positively charged
(b) negatively charged
(c) uncharged
(d) uncharged at 0K but charged at higher temperatures

Answer: (c)

Q.4. Electric conduction in a semiconductor takes place due to
(a) electrons only
(b) holes only
(c) both electrons and holes
(d) neither electrons nor holes

Answer: (c)

Q.5. The impurity atoms with which pure silicon may be doped to make it a p-type semiconductor are those of
(a) phosphorus

(b) boron

(c) antimony

(d) nitrogen

Answer: (b)

Q.6. The electrical conductivity of pure germanium can be increased by
(a) increasing the temperature
(b) doping acceptor impurities
(c) doping donor impurities
(d) All of the above

Answer: (d)

Q.7. The resistivity of a semiconductor at room temperature is in between
(a) 10^–2 to 10^–5 Ω cm

(b) 10^–3 to 10⁶ Ω cm

(c) 10⁶ to 10⁸ Ω cm

(d) 10¹⁰ to 10¹² Ω cm

Answer: (b)

Q.8. Number of electrons in the valence shell of a pure semiconductor is
(a) 1

(b) 2

(c) 3

(d) 4

Answer: (d)

Q.9. In a semiconductor, the forbidden energy gap between the valence band and the conduction band is of the order is
(a) 1 MeV

(b) 0.1 MeV

(c) 1 eV

(d) 5 eV

Answer: (c)

Q.10. The forbidden energy gap for germanium crystal at 0 K is
(a) 0.071 eV

(b) 0.71 eV

(c) 2.57 eV

(d) 6.57 eV

Answer: (b)

Q.11. In an insulator, the forbidden energy gap between the valence band and conduction band is of the order of
(a) 1 MeV

(b) 0.1 MeV

(c) 1 eV

(d) 5 eV

Answer: (d)

Q.12. What is the resistivity of a pure semiconductor at absolute zero ?
(a) Zero
(b) Infinity
(c) Same as that of conductors at room temperature
(d) Same as that of insulators at room temperature

Answer: (b)

Q.13. Temperature coefficient of resistance of semiconductor is
(a) zero

(b) constant

(c) positive

(d) negative

Answer: (d)

Q.14. In a p-type semiconductor, the acceptor valence band is
(a) close to the valence band of the host crystal
(b) close to conduction band of the host crystal
(c) below the conduction band of the host crystal
(d) above the conduction band of the host crystal

Answer: (a)

Q.15. In an n-type semiconductor, donor valence band is
(a) above the conduction band of the host crystal
(b) close to the valence band of the host crystal
(c) close to the conduction band of the host crystal
(d) below the valence band of the host crystal

Answer: (c)

In This Post we are  providing Chapter-13 Nuclei NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON NUCLEI

Q.1. Cathode ray consists of
(a) photons
(b) electrons
(c) protons
(d) α-particles

Answer: (b)

Q.2. A discharge takes place between the two electrodes on applying the electric field to the gas in the discharge tube. The cause of this fluorescence was attributed to
(a) the radiations which appeared to be coming from the anode
(b) the radiation which appeared to be coming from the cathode
(c) the protons coming from the cathode
(d) the protons coming from the anode

Answer: (b)

Q.3. The presently accepted value of charge/mass (e/m) is
(a) 1.66 x 10^–19 c/kg
(b) 9.1 x 10¹¹ c/kg
(c) 1.76 x 10¹¹ c/kg
(d) 9.1 x 10¹⁹ c/kg

Answer: (c)

Q.4. In which of the following, emission of electrons does not take place?
(a) Thermionic emission
(b) X-rays emission
(c) Photoelectric emission
(d) Secondary emission

Answer: (b)

Q.5. Photoelectric emission occurs only when the incident light has more than a certain minimum
(a) power
(b) wavelength
(c) intensity
(d) frequency

Answer: (d)

Q.6. Which of the following when falls on a metal will emit photoelectrons ?
(a) UV radiations
(b) Infrared radiation
(c ) Radio waves
(d) Microwaves

Answer: (a)

Q.7. Particle like behavior of light arises from the fact that each quanta of light has definite …X… and a fixed value of …Y.. just like a particle, Here, X and Y refer to
(a) frequency, energy
(b) shape, volume
(c) energy, frequency
(d) energy, momentum

Answer: (d)

Q.8. The wave nature of light was established by (i) Maxwell’s equations (ii) Fraunhofer’s lines (iii) Hertz experiment (iv) Einstein’s theory
(a) (i) and (ii) only
(b) (ii) and (iv) only
(c) (i) and (iii) only
(d) (iii) and (iv) only

Answer: (c)

Q.9. The work-function of a metal is
(a) the minimum current required to take out electron from the metal surface
(b) the maximum frequency required to take out electron from the metal surface
(c) the minimum amount of energy required to take out the electron from the metal surface
(d) None of these

Answer: (c)

Q.10. The work function of a metal is independent of
(i) nature of the surface of the metal
(ii) dimensions of the metal
(iii) properties of the metal
(iv) abundance of the metal
(a) (i) only
(b) (i) and (iii)
(c) (ii) and (iii)
(d) (ii) and (iv)

Answer: (d)

Q.11. The theory of quantization of electric charge was given by
(a) William Crookes
(b) J. J. Thomson
(c) R.A. Millikan
(d) Wilhelm Hallwachs

Answer: (c)

Q.12. In photoelectric effect, electrons are ejected from metals, if the incident light has a certain minimum
(a) wavelength
(b) frequency
(c) amplitude
(d) angle of incidence

Answer: (b)

Q.13. Which of the following metals is not sensitive to visible light?
(a) Cesium
(b) Sodium
(c) Rubidium
(d) Cadmium

Answer: (d)

Q.14. A photosensitive substance emits _____when illuminated by light.
(a) only protons
(b) only neutrons
(c) electrons and protons
(d) only electrons

Answer: (d)

Q.15. The photoelectric current does not depend upon the
(i) frequency of incident light
(ii) work function of the metal
(iii) stopping potential
(iv) intensity of incident light
(a) (i) and (iv) only
(b) (ii) and (iii) only
(c) (iii) only
(d) (ii) only

Answer: (c)

In This Post we are  providing Chapter-12 Atom NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON ATOMS

Question 1.
De-Broglie equation states the:
(a) dual nature
(b) particle nature
(c) wave nature
(d) none of these

Answer: (a) dual nature

Question 2.
Protons and alpha particles have the same de-Broglie wavelength. What is same for both of them ?
(a) Energy
(b) Time period
(c) Frequency
(d) Momentum

Answer: (d) Momentum

Question 3.
Kinetic energy of emitted electrons depends upon :
(a) frequency
(b) intensity
(c) nature of atmosphere surrounding the electrons
(d) none of these

Answer: (a) frequency

Question 4.
De-Broglie wavelength of a body of mass m and kinetic energy E is given by (symbols have their usual meanings):
(a) h/2m√E
(b) h/2mE
(c) 2mE/√h
(d) h/mE

Answer: (a) h/2m√E

Question 5.
The ratio of specific charge of an alpha particle to the proton is:
(a) 1 : 2
(b) 2 : 1
(c) 4 : 1
(d) 1 : 4

Answer: (a) 1 : 2

Question 6.
In Thomson’s experiment number of parabola gives :
(a) the no. of electrons present in element
(b) the no. of proton present in element
(c) the no. of neutrons present in element
(d) the no. of isotopes of the element present

Answer: (d) the no. of isotopes of the element present

Question 7.
The work function of photoelectric material is 3.3 eV. The threshold frequency will be equal to:
(a) 8 × 10¹⁴ Hz
(b) 8 × 10¹⁰ Hz
(c) 5 × 10¹⁰ Hz
(d) 4 × 10¹⁴ Hz

Answer: (a) 8 × 10¹⁴ Hz

Question 8.
The strength of photoelectric current depends upon :
(a) angle of incident radiation
(b) frequency of incident radiation
(c) intensity of incident radiation
(d) distance between anode and cathode

Answer: (b) frequency of incident radiation

Question 9.
The momentum of an electron that emits a wavelength of 2 Å. will be:
(a) 6.4 × 10^-36 kgms^-1
(b) 3.3 × 10^-24 kgms^-1
(c) 3.3 × 10^-34 kgms^-1
(d) none of these

Answer: (b) 3.3 × 10^-24 kgms^-1

Question 10.
Name the scientists who first studied the passage of electricity through fluids to establish the electrical nature of matter:
(a)Millikan
(b) Planck
(c) Faraday
(d) Boyle

Answer: (c) Faraday

Question 11.
Millikan’s oil drop experiment makes use of:
(a) Stokes’ law
(b) Boyle’s law
(c) Gas equation
(d) Bernoulli’s theorem

Answer: (a) Stokes’ law

Question 12.
X-rays are:
(a) deflected by an electric field
(b) deflected by a magnetic field
(c) deflected by both electric and magnetic fields
(d) not deflected by electric and magnetic fields

Answer: (d) not deflected by electric and magnetic fields

Question 13.
In photo electric emission, for alkali metals the threshold frequency lies in the:
(a) visible region
(b) ultraviolet region
(c) infrared region
(d) far end of the infrared region

Answer: (a) visible region

Question 14.
Which of the following radiations cannot eject photo electrons?
(a) ultraviolet
(b) infrared
(c) visible
(d) X-rays

Answer: (b) infrared

Question 15.
What is the de-Broglie wavelength of an electron accelerated from rest through a potential difference of V volts?
(a) 12.3V2 Å
(b) 12.3V Å
(c) 12.2V2 Å
(d) None of these

Answer: (a) 12.3V2 Å

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In This Post we are  providing Chapter-11 Dual Nature of Radiation and Matter NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

NCERT MCQ ON DUAL NATURE OF RADIATION AND MATTER

Question 1: A strong argument for the particle nature of cathode rays is that they

(a) produce fluorescence
(b) travel through vacuum
(c) get deflected by electric and magnetic fields
(d) cast shadow

Answer=C

Question 2 : In an electron gun the control grid is given a negative potential relative to cathode in order to

(a) decelerate electrons
(b) repel electrons and thus to control the number of electrons passing through it
(c) to select electrons of same velocity and to converge them along the axis.
(d) to decrease the kinetic energy of electrons

Answer=B

Question 3: When the speed of electrons increase, then the value of its specific charge

(a) increases
(b) decreases
(c) remains unchanged
(d) increases up to some velocity

Answer=B

Question 4: Photoelectric effect is the phenomenon in which

(a) photons come out of a metal when it is hit by a beam of electrons.
(b) photons come out of the nucleus of an atom under the action of an electric field.
(c) electrons come out of a metal with a constant velocity
(d) which depends on the frequency and intensity of incident light wave.

Answer=D

Question 5 : The photoelectrons emitted from a metal surface are such that their velocity

(a) is zero for all
(b) is same for all
(c) lies between zero and infinity
(d) lies between zero and a finite maximum

Answer=D

Question 6 : Photoelectric emission occurs only when the incident light has more than a certain minimum

(a) power   

(b) wavelength
(c) intensity

(d) frequency

Answer=D

Question 7: When light is incident on a metal surface the maximum kinetic energy of emitted electrons

(a) vary with intensity of light
(b) vary with frequency of light
(c) vary with speed of light
(d) vary irregularly

Answer=B

Question 8: A photoelectric cell is a device which

(a) converts light into electricity
(b) converts electricity into light
(c) stores light
(d) stores electricity

Answer=A

Question 9 : The maximum energy of electrons released in a photocell is independent of

(a) the frequency of the incident light
(b) the intensity of the incident light
(c) the nature of the cathode
(d) All of the above

Question 10: The work functions of Silver and Sodium are 4.6 and 2.3 eV, respectively. The ratio of the slope of the stopping potential versus frequency plot for Silver to that of Sodium is

(a) 1

(b) 2

(c) 4

(d) zero

Answer=A

Question 11: In a photoelectric experiment the stopping potential for the incident light of wavelength 4000Å is 2 volt. If the wavelength be changed to 3000 Å, the stopping potential will be

(a) 2 V

(b) zero
(c) less than 2 V

(d) more than 2 V

Answer=D

Question 12: A photocell is illuminated by a small bright source placed 1 m away. When the same source of light is placed 2 m away, the number of electrons emitted by photocathode are reduced by a factor of

(a) 1/8

(b) 1/16

(c) 1/2

(d) 1/4

Answer=D

Question 13: Light from a hydrogen discharge tube is incident on the cathode of a photoelectric cell, the work function of the cathode surface is 4.2 eV. In order to reduce the photocurrent to zero the voltage of the anode relative to the cathode must be made

(a) – 4.2 V

(b) – 9.4 V

(c) – 17.8 V

(d) + 9.4 V

Answer=B

Question 14: In Davison-Germier experiment, an electron beam is incident on a crystal. The reflected beam consists of

(a) photons

(b) protons
(c) x-rays

(d) electrons

Answer=D

Question 15: In the Davisson and Germier experiment, the velocity of electrons emitted from the electron gun can be increased by

(a) increasing the potential difference between the anode and filament
(b) increasing the filament current
(c) decreasing the filament current
(d) decreasing the potential difference between the anode and filament

Answer=A

In This Post we are  providing Chapter-10 Wave Optics NCERT MCQ for Class 12 Physics which will be beneficial for students. These solutions are updated according to 2021-22 syllabus. These MCQS  can be really helpful in the preparation of Board exams and will provide you with a brief knowledge of the chapter.

_{NCERT MCQ ON WAVE OPTICS}

Question 1.
What happens if one of the slits, say S₁ in Young’s double , slit experiment-is covered with a glass plate which absorbs half the intensity of light from it?
(a) The bright fringes become less-bright and the dark fringes have a finite light intensity
(b) The bright fringes become brighter and the dark fringes become darker
(c) The fringe width decreases
(d) No fringes will be observed

Answer: (a) The bright fringes become less-bright and the dark fringes have a finite light intensity

Question 2.
What happens to the interference pattern the two slits S₁ and S₂ in Young’s double experiment are illuminated by two independent but identical sources?
(a) The intensity of the bright fringes doubled
(b) The intensity of the bright fringes becomes four times
(c) Two sets of interference fringes overlap
(d) No interference pattern is observed

Answer: (d) No interference pattern is observed

Question 3.
What is the reason for your answer to the above question?
(a) The two sources do not emit light of the same wavelength
(b) The two sources emit waves which travel with different speeds
(c) The two sources emit light waves of different amplitudes
(d) There is not constant phase difference between the waves emitted by the two sources

Answer: (d) There is not constant phase difference between the waves emitted by the two sources

Question 4.
A single slit diffraction pattern is obtained using a beam of red light What happened the red light is replaced by the blue light?
(a) There is no change in diffraction pattern
(b) Diffraction fringes become narrower and crowded
(d) Diffraction fringes become broader and farther apart
(d) The diffraction pattern disappear

Answer: (b) Diffraction fringes become narrower and crowded

Question 5.
When a polaroid is rotated, the intensity of light varies but never reduces to zero. It shows that the incident light is:
(a) unpolarized
(b) completely plane polarized
(c) partially plane polarized
(d) None of the above

Answer: (c) partially plane polarized

Question 6.
When a polaroid is rotated, the intensity of light does not vary. The incident light may be:
(a) unpolarized
(b) completely polarized
(c) partially plane polarized
(d) None of the above

Answer: (a) unpolarized

Question 7.
In Young’s double slit experiment, a maximum is obtained when the path difference between the interfering waves is (n ∈ l):
(a) nλ
(b) n λ2
(c) (2n + 1) λ2
(d) (2n – 1) λ4

Answer: (a) nλ

Question 8.
For sustained interference, we need two sources which
emit radiations :
(a) of the same intensity
(b) of the same amplitude
(c) having a constant phase difference
(d) None of these

Answer: (c) having a constant phase difference

Question 9.
Two sources of light are said to be coherent when both give out light waves of the same:
(a) amplitude and phase
(b) intensity and wavelength
(c) speed
(d) wavelength and a constant phase difference

Answer: (d) wavelength and a constant phase difference

Question 10.
The intensity of light emerging from the two slits, in Young’s experiment is in the ratio 1 : 4. The ratio of, the intensity of the minimum to that of the consecutive maximum will be:
(a) 1 : 4
(b) 1 : 9
(c) 1 : 16
(d) 2 : 3

Answer: (b) 1 : 9

Question 11.
Poisson’s bright spot was discovered by:
(a) Fresnel
(b) Rayleigh
(c) Poisson
(d) Fraunhoffer

Answer: (c) Poisson

Question 12.
The theory of expanding universe is confirmed by the observation of the spectral lines of the star, which shows :
(a) green shift
(b) red shift
(c) violet shift
(d) yellow shift

Answer: (b) red shift

Question 13.
The application of Doppler effect are:
(a) Doppler spectrometer
(b) Doppler radius
(c) Doppler velocimeter
(d) All of these

Answer: (d) All of these

Question 14.
Which of the following is conserved when light waves interfere?
(a) phase
(b) intensity
(c) amplitude
(d) none of these

Answer: (d) none of these

Question 15.
In Young double slit experiment, a minimum is obtained when the phase difference of the superposing waves, is (n ∈ l):
(a) nπ
(b) (n + 12)π
(c) (2n + 1)π
(d) zero

Answer: (c) (2n + 1)π

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