Practice MCQ Questions and answers on Physics-GK

Magnetic keepers are soft iron bars placed at either end of the pair of magnets. It is used to avoid self-demagnetisation of magnets.

In physics, there are seven fundamental physical quantities that are measured in base or physical fundamental units: length, mass, time, electric current, temperature, amount of substance and luminous intensity.

When the piece of iron is lowered into the water, the water level in the bucket increases. And so the pressure at the bottom of bucket also increases. Thus the total thrust at the bottom also increases. Therefore the spring balance reading increases.

1 amu is equivalent to 931 MeV.

1 m/s equals 18/5 km/hr.

A light year is a measure of distance.

A seconds pendulum is a pendulum whose period is precisely two seconds; one second for a swing in one direction and one second for the return swing, a frequency of 12 Hz.

A nanosecond (ns) is an SI unit of time equal to one billionth of a second.

One nanometer is equal to 10^-7 cm.

The time period of a pendulum is directly proportional to the square root of its length. So, if the length increases, its time period also increase. It means that it takes longer to complete one oscillation. So when its length is halved, its time period is decreased by a factor of 2.