Nuclei — Physics STD 12 Science — Question

Assertion :   If a point charge q is placed in front of an infinite grounded conducting plane surface, the point charge will experience a force.

Reason     : This force is due to the induced charge on the conducting surface which is at zero potential.

(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.

The kinetic energy force on the particle continuously increases with time.

1. The resultant force on the particle must be parallel to the velocity at all instants.
2. The resultant force on the particle must be at an angle less than 90° all the time.
3. Its height above the ground level must continuously decrease.
4. The magnitude of its linear momentum is increasing continuously.

In the given figure, a current of constant magnitude is flowing in the wire AB. Direction of induced current flowing through the wire is:

The charge is negative, then the electric lines of forces are:

The best suitable metal for photoelectric effect is:

X-rays are known to be electromagnetic radiations. Therefore the X-ray photon has

(a) Electric charge

(b) Magnetic moment

(c) Both electric charge and magnetic moment

(d) Neither electric charge nor magnetic moment

There are seven orbitals in a subshell then the value of l for it will be:

If the distance of the far point for a myopia patient is doubled, the focal length of the lens required to cure it will become 

(a) Half	(b) Double
(c) The same but a convex lens	(d) The same but a concave lens

The diode used in the circuit shown in the figure has a constant voltage drop at 0.5 V at all currents and a maximum power rating of 100 milliwatts. What should be the value of the resistor R, connected in series with diode for obtaining maximum current?