HARD
12th West Bengal Board
IMPORTANT
Earn 100

 State, with the help of a circuit diagram, the working principle of a metre bridge. Obtain the expression used for determining the unknown resistance.

Important Questions on Current Electricity

EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 22
 What happens if the galvanometer and cell are interchanged at the balance point of the bridge?
EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 22

 Why is it considered important to obtain the balance point near the mid-point of the wire?

MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 1
A metallic wire 10 cm long has a resistance of 5Ω. If the wire is now stretched so that its length is doubled, what happens to the value of the resistance? (Assume that the volume and specific resistance of the wire remain unchanged) 
MEDIUM
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 2
A wire of resistance 5Ω is stretched 20%. If the volume remains constant, find the new resistance.
EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 3
When a 1.08 V Daniel cell is connected in a circuit, 0.5 A current flows through it and the terminal potential difference of the external circuit is found to be 0.7 V. What is the resistance of the cell ? 
EASY
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 4
The internal resistance of a 100 V battery is 5Ω. Its emf as measured by a voltmeter connected across it shows 20% error. What is the resistance of the voltmeter?
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 5
Two coils have equivalent resistance 12Ω and 53Ω respectively in series and parallel combinations. What are the resistances of the coils? 
HARD
12th West Bengal Board
IMPORTANT
A Text Book of PHYSICS PART 2 : CLASS 12>Chapter 5 - Current Electricity>EXERCISE 5>Q 6
A battery and a series combination of resistances 2.25 Ω and 1 Ω are connected to a parallel combination of resistance 3 Ω and 1 Ω. The internal resistance of the battery is 0.1 Ω and its emf is 2 V. Calculate the magnitude of current flowing through the resistances.