Electric Charges and Fields — Physics STD 12 Science — Question

A transformer has 100 turns in the primary coil and carries 8 A current. If input power is one kilowatt, the number of turns required in the secondary coil to have 500V output will be

(a) 100

(b) 200

(c) 400

(d) 300

When stopping potential is applied in an experiment on photoelectric effect, no photocurrent is observed. This means that:

Indicate which one of the following system is digital

(a) Pulse position modulation	(b) Pulse code modulation
(c) Pulse width modulation	(d) Pulse amplitude modulation

In the n^th orbit, the energy of an electron  for hydrogen atom. The energy required to take the electron from first orbit to second orbit will be

(a) 10.2 eV

(b) 12.1 eV

(c) 13.6 eV

(d) 3.4 eV

The refractive index of the material of the prism and liquid are 1.56 and 1.32 respectively.  What will be the value of q for the following refraction

(a) sinθ  ≥

(b) sinθ ≥

(c) sinθ ≥

(d) sinθ ≥

Nuclear fission experiments show that the neutrons split the uranium nuclei into two fragments of about same size. This process is accompanied by the emission of several

(a) Protons and positrons	(b) a - particles
(c) Neutrons	(d) Protons and a-particles

1 tesla is equal to:

A source of sound moves towards an observer.

1. The frequency of the source is increased.
2. The velocity of sound in the medium is increased.
3. The wavelength of sound in the medium towards the observer is decreased.
4. The amplitude of vibration of the particles is increased.

Which of the following does not fit into a group: