Physics Questions

Weight is mass x g. Since mass is constant and g is only 16thof that on the earth. The weight on the moon is only 16th of that on the earth. 

Therefore 2N i.e (b) is the answer.

Because the refractive index of glass is highest, light travels slowly in Glass. 

We know that the speed of light depends on the refraction index. The higher the index of refraction is, the slower the speed of light is.

R.I of air and vacuum = 0 (air is a teeny bit more but can be taken as 0)
R.I of water = 1.33
R.I of glass = 1.4.

Hence, Light travels slowest in Glass.

Lightning is extremely hot — a flash can heat the air around it to temperatures five times hotter than the sun’s surface. This heat causes surrounding air to rapidly expand and vibrate, which creates the pealing thunder we hear a short time after seeing a lightning flash.

Lightning heats the surrounding air to about 30,000 degrees Centigrades.

The hertz (Hz) is defined as one cycle per second and is a SI unit of frequency. Here kilohertz is also a unit of frequency of waves and is defined as 1000 cycles per second. Radio waves are measured in kilohertz (KHz).

When their is a colloid in the solution, then it will show the Brownian movement, such as dust particle in the air will show the Brownian movement.

Hence, Brownian movement arises due to the impact of the molecules of the dispersion medium with the colloidal particles. It has been postulated that the impact of the molecules of dispersion medium on the colloidal particles are unequal.

This leads to the zig-zag (random) motion of the colloidal particles.

The given statement, The heat from the sun reaches earth through Convection is FALSE.

Heat from the sun actually reaches the earth through Radiation. The process occurs through electromagnetic radiation, specifically, in which molecules are warmed when the heat reaches them, and these molecules then warm other molecules touching them, which continues until we feel the sun's heat.