Magnetism And Matter — Physics STD 12 Science — Question

The natural frequency of an LC - circuit is 1,25,000 cycles per second. Then the capacitor C is replaced by another capacitor with a dielectric medium of dielectric constant k. In this case, the frequency decreases by 25kHz. The value of k is:

The SI unit of electric flux is:

A uniform magnetic field B is acting from south to north and is of magnitude 1.5 . If a proton having mass  = 1.7   and charge  = 1.6   moves in this field vertically downwards with energy 5 MeV, then the force acting on it will be

(a) 7.4

(b) 7.4

(c) 7.4

(d) 7.4

A potential difference of 300 volts is applied to a combination of 2.0mF and 8.0mF capacitors connected in series. The charge on the 2.0mF capacitor is

(a) 2.4

(b) 4.8

(c) 7.2

(d) 9.6

The spectrum of radiation 1.0   is in the infrared region. The energy of one photon of this in joules will be

(a) 6.62

(b) 6.62

(c)

(d) 3

To convert mechanical energy into electrical energy, one can use:

1. DC dynamo.
2. AC dynamo.
3. Motor.
4. Transformer.

The true statement is

(a) The order of colours in the primary and the secondary rainbows is the same

(b) The intensity of colours in the primary and the secondary rainbows is the same

(c) The intensity of light in the primary rainbow is greater and the order of colours is the same than the secondary rainbow

(d) The intensity of light for different colours in primary rainbow is greater and the order of colours is reverse than the secondary rainbow

Which of the following shown particle nature of light

(a) Refraction

(b) Interference

(c) Polarization

(d) Photoelectric effect

Huygen's principle cannot explain __________ .

The mass number of He is 4 and that for sulphur is 32. The radius of sulphur nucleus is larger than that of helium, by times

(a)

(b) 4

(c) 2

(d) 8