Resistance in a circuit

The effective resistance of a circuit containing resistances in parallel is

What happens to the resistance of a circuit if the current through it is doubled ?

If the resistance of a circuit having 12 V source is increased by 4Omega the current drops by 0.5 A. What is the original resistance of circuit

The emfs and resistance in the circuit (as shown in the figure) have the following values.

Find current in 10Omega resistance in the circuit shown in figure-3.114.

Keeping the p.d. constant, the resistance of a circuit is halved. The current will become:

Keeping the potential difference constant, the resistance of a circuit is doubled. The current will becomes: