HARD
12th Andhra Pradesh Board
IMPORTANT
Earn 100

Derive an expression for the effective resistance when three resistors are connected in series.

Important Questions on Current Electricity

MEDIUM
12th Andhra Pradesh Board
IMPORTANT
'm' cells each of emf E and internal resistance 'r' are connected in parallel. What is the total emf and internal resistance? Under what conditions is the current drawn from mixed grouping of cells a maximum?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
Define electric resistance and write its SI unit. How does the resistance of a conductor vary if the conductor is stretched to 4 times of its length?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
How does the resistance of a conductor vary if temperature of conductor is increased?
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
When the resistance connected in series with a cell is halved, the current is equal to or slightly less or slightly greater than double. Why?
HARD
12th Andhra Pradesh Board
IMPORTANT
Two cells of EMF's 4.5 V and 6.0 V and internal resistance 6 Ω and 3 Ω respectively have their negative terminals joined by a wire of 18 Ω and positive terminals by a wire of 12 Ω resistance. A third resistance wire of 24 Ω connects middle points of these wires. Using Kirchhoff's laws, find the potential difference (in V) at the ends of this third wire.
HARD
12th Andhra Pradesh Board
IMPORTANT
State Kirchhoff's law for an electrical network. Using these laws deduce the condition for balance in a Wheatstone bridge.
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
State the working principle of potentiometer, explain with the help of circuit diagram how the emf of two primary cells are compared by using the potentiometer.
MEDIUM
12th Andhra Pradesh Board
IMPORTANT
State the working principle of potentiometer, explain with the help of circuit diagram how the potentiometer is used to determine the internal resistance of the given primary cell.