Electrostatic Potential and Capacitance — Physics STD 12 Science — Question

A proton and an a-particle are accelerated through a potential difference of 100 V. The ratio of the wavelength associated with the proton to that associated with an a-particle is

(a)

(b) 2 : 1

(c) 2

(d)

A sample of radioactive element has a mass of 10 gm at an instant t = 0.The approximate mass of this element in the sample after two mean lives is

(a) 2.50 gm

(b) 3.70 gm

(c) 6.30 gm

(d) 1.35 gm

The phenomenon of interference is shown by

(a) Longitudinal mechanical waves only	(b) Transverse mechanical waves only
(c) Electromagnetic waves only	(d) All the above types of waves

The points resembling equal potentials are

(a) P and Q

(b) S and Q

(c) S and R

(d) P and R

When a charged particle moves at right angle to a magnetic field quantity that changes is:

Shown in the figure is a circular loop of radius r and resistance R. A variable magnetic field of induction   is established inside the coil. If the key (K) is closed, the electrical power developed right after closing the switch is equal to

(a)

(b)

(c)

(d)

If the potential difference applied to the tube is doubled and the separation between the filament and the target is also doubled, the cutoff wavelength:

1. Will remain unchanged.
2. Will be doubled.
3. Will be halved.
4. Will become four times the original.

Figure represents a glass plate placed vertically on a horizontal table with a beam of unpolarised light falling on its surface at the polarising angle of 57^o with the normal. The electric vector in the reflected light on screen S will vibrate with respect to the plane of incidence in a

(a) Vertical plane

(b) Horizontal plane

(c) Plane making an angle of 45o with the vertical

(d) Plane making an angle of 57o with the horizontal

Insulation breakdown may occur at _______?