Electromagnetic Waves — Physics STD 12 Science — Question

The mass of a neutral carbon atom in ground state is:

1. Exact 12u
2. Less than 12u
3. More than 12u
4. Depends on the form of carbon such as graphite or charcoal.

On oscillating any metallic sphere in the magnetic field, its oscillatory motion is :

Two metal pieces having a potential difference of 800 V are  0.02 m apart horizontally. A particle of mass  is suspended in equilibrium between the plates. If e is the elementary charge, then charge on the particle is

(a) e

(b) 3e

(c) 6e

(d) 8e

The total current supplied to the circuit by the battery is

(a) 1 A

(b) 2 A

(c) 4 A

(d) 6 A

Assertion : V-i characteristic of P-N junction diode is same as that of any other conductor.

Reason     : P-N junction diode behave as conductor at room temperature.

(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 high temperature required to initiate the nuclear fusion reaction is to overcome the _______ present between the atoms.

Under which of the following conditions will a convex mirror of focal length f produce an image that is erect, diminished and virtual

(a) Only when 2f  > u > f	(b) Only when u = f
(c) Only when u < f	(d) Always

A short bar magnet placed with its axis at 30° with a uniform external magnetic field of 0.16 Tesla experiences a torque of magnitude 0.032 Joule. The magnetic moment of the bar magnet will be

(a) 0.23 Joule/Tesla

(b) 0.40 Joule/Tesla

(c) 0.80Joule/Tesla

(d) Zero

In a cyclotron, the angular frequency of a charged particle is independent of

(a) Mass

(b) Speed

(c) Charge

(d) Magnetic field

In a hydrogen atom, which of the following electronic transitions would involve the maximum energy change: