The power dissipated in the circuit shown in the figure $$40 \mathrm{~W}$$. The value of $$R$$ is.

In the arrangement shown in figure, when the switch S₂ is open, the galvanometer, shows no deflection for $$l$$ = 50 cm when the switch S₂ is closed, the galvanometer shows no deflection for $$l$$ = 0.416 m. The internal resistance (r) of 6 V cell is

A shunt is connected in parallel with a galvanometer. Why?

In the following circuit, assuming point A to be at zero potential, then what is the potential at point B?

In the circuit shown, if the 10 $$\Omega$$ resistor is replaced by a resistor of 15 $$\Omega$$, then what is the amount of current drawn from the battery?

A moving coil galvanometer has a resistance of 60 $$\Omega$$ and it indicates full deflection on passing a current of 4.5 mA. A voltmeter is made using this galvanometer and a 4.5 k$$\Omega$$ resistance. The maximum voltage, that can be measured using this voltmeter, will be close to

A potentiometer wire, 10 m long, has a resistance of 40$$\Omega$$. It is connected in series with a resistance box and a 4 V storage cell. If the potential gradient along the wire is 0.4 mV cm^$$-$$1, the resistance unplugged in the box is