Physics Questions

A magnifying glass is a convex lens that is used to produce a magnified image of an object. It is also called a hand lens in laboratory contexts.

When you compress or stretch a spring, as soon as the stress is relieved, the spring attains its normal shape instantly. Its Elastic potential energy helps it do so. Generally, these elastic substances follow the Hooke’s law.

According to this Law, the force needed to change the shape of spring is proportional to the displacement of the spring. The displacement referred here is how far the spring is compressed or stretched from its normal shape. Mathematically, Hook’s Law can be summarised as F= – k x. Here ‘k’ is the spring constant and ‘x’ is the displacement.

Alternating Current (AC) is the current in which flow of current is altered periodically whereas in DC current i.e, direct current the flow of current is only in one direction.

Some of the sources of AC current are :

1. Hydro-electric generators

2. Thermal power generators

3. Nuclear  power generators...

In physics, the dynamo theory proposes a mechanism by which a celestial body such as Earth or a star generates a magnetic field.

Earth's crust core contains a large amount of iron and nickel is the evidence of the dynamo theory.

Pitot tube is used to measure stagnation pressure.

A star is a self luminous astronomical object and shines due to internal radiation from the enrgy sources. All stars are held together by their own gravity called Gravitational force.

The size of the pupil of the automatically adjusts itself according to the intensity of light passing through it; if the intensity is more, the size is less, if less, it is more. So in our case the pupil should dilate i.e , increase in size to be able to see in the dark. This switchover takes some time. But here the entry into the dark room is immediate. So the eye has no time to adjust itself and hence is not able to see at all for a while.