To verify the laws of combination (parallel) of resistances using a metre bridge | Cbse Class 12th physics Practical

Objective

To verify the laws of combination (parallel) of resistances using a metre bridge.

Apparatus Required

A metre bridge, a Leclanche cell or battery eliminator, a galvanometer, a resistance box, a jockey, two resistance wires or two resistance coils known resistances, a set square, sand paper and connecting wires.

Formula Used

Diagram

Here R₁ = 1 Ω and R₂ = 2 Ω

Calculation

Result

Hence, laws of combination (parallel) of resistance is verified using a metre bridge.

Precautions

• All connections should be neat and tight.
• All the plugs in the resistance box should be tight.
• Clean the connecting wires and the connecting points of metre bridge properly with sandpaper.
• The jockey should be held perpendicular to wire of metre bridge.
• Try to obtain the balance point between 40 cm and 60 cm.
• Move the jockey gently on the wire and do not keep the jockey and the wire in contact for a long time.

Sources of errors

• The keys of the resistance box may not be clean and tight.
• The wire may not be uniformly thick throughout.
• The screws of the instrument may be loose.