Electricity/Electronics — 21 Physics PYQs with Answers | UKPSC PYQ Hub

Question 1

Consider a tightly wound 100 turn coil of radius 10 cm, carrying a current of 1A. What will be the magnitude of the magnetic field at the centre of the coil? 10–4 10–3

Accepted Answer

6.28 × T. Given, Number of turns in the coil = 100 Radius of coil = 10 cm Current flowing through the coil = 1A Therefore, µ IN Magnetic field at the center of the coil B = 2r r = 10cm = 0.1m 4π×10–7×1×100 B = 2×0.1m

Question 2

28×10-4 = T 70. A solar cell unit is basically a:

Accepted Answer

A semiconductor Diode. A solar cell is a device that converts light energy into electrical energy. It is a semi-conductor device based on the principle of photovoltaic effect, with the help of which the work of converting light into electric current is done.

Question 3

The purpose of Choke in tube light is ________.

Accepted Answer

to increase the voltage momentarily. The purpose of choke in tube light is to limit the current by providing a very high voltage momentarily.

Question 4

Which one of the following element is used in solar cells?

Accepted Answer

Silicon. Silicon is the most common semiconductor material used in solar cells, representing approximately 95% of the modules sold today. It is also the second most abundant material on earth (after oxygen) and t he most common semiconductor used in computer chips.

Question 5

The semiconductor chip employed in Integrated Circuits is made of?

Accepted Answer

Silicon. The semiconductor chip employed in Integrated Circuits is made of Silicon.

Question 6

The substance which has large number of free electrons and offer a low resistance is called :

Accepted Answer

Conductor. The substance which has large number of free electrons and offer a low resistance is called conductor. Materials, notably metals, some of the electrons are practically free to move within the bulk material. These materials, generally called conductors, develop electric currents in them when an electric field is applied.

Question 7

Consider the following statements– Statement (A) : Lightning conductors save buildings from damage. Reason (R) : It sends electric charge into the earth. Choose the correct answer using the codes given below– Codes:

Accepted Answer

is false.. Lightning conductors save buildings from damage as it provides the path to the electric charge to reach the ground without affecting building.

Question 8

Fullform of C.F.L. whose incandescence is used in place of lamps/bulbs to save electric energy is?

Accepted Answer

Compact Fluroscent Lamp. Full form of CFL is compact fluorescent lamps. It is an energy-saving bulb that consumes much less energy than the conventional incandescent lamps. It is made up of a glass tube which contains mixture of argon gas and mercury vapour, along with tow electrodes.