Ray Optics and Optical Instruments — Physics STD 12 Science — Question

The phase angle between current and voltage in a purely inductive circuit is:

A point P is situated on the axis of an electric dipole at a distance x from its mid-point, the electric potential at point P is proportional to:

The same mass of copper is drawn into two wires 1 mm and 2 mm thick. Two wires are connected in series and current is passed through them. Heat produced in the wire is in the ratio

(a) 2 : 1

(b) 1 : 16

(c) 4 : 1

(d) 16 : 1

Which of the following will change the time period as they are taken to moon?

1. A simple pendulum.
2. A physical pendulum.
3. A torsional pendulum.
4. A spring-mass system.

Equipotential surfaces of a single point charge are _____ surfaces centred at the charge.

Two independent parallel wires in which the current is flowing in the same direction. They will:

Assertion  :  There is no current in the metals in the absence of electric field.

Reason      : Motion of free electron are randomly.

(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.

(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.

(c) If assertion is true but reason is false.

(d) If the assertion and reason both are false.

In a simple harmonic motion:

1. The maximum potential energy equals the maximum kinetic energy.
2. The minimum potential energy equals the minimum kinetic energy.
3. The minimum potential energy equals the maximum kinetic energy.
4. The maximum potential energy equals the minimum kinetic energy.

An LR circuit with a battery is connected at t = 0. Which of the following quantities is not zero just after the connection?

1. Current in the circuit.
2. Magnetic field energy in the inductor.
3. Power delivered by the battery.
4. Emf induced in the inductor.