Science (English Medium) कक्षा १२ - CBSE Question Bank Solutions for Physics

Light rays from a point object ______.

Light travels through a glass plate of thickness t and having a refractive index μ. If c is the velocity of light in vacuum, the time taken by the light to travel this thickness of glass is ______.

Interference effects of light from two sources can be observed if the sources are ______.

If we have two coherent sources S₁ and S₂ vibrating in phase, then for an arbitrary point P destructive interference is observed whenever the path difference is ______.

If we have two coherent sources S₁ and S₂ vibrating in phase with same amplitude, then for an arbitrary point P with path difference corresponding to ϕ, the resultant intensity if the intensity due to each is I₀ would be ______.

State two conditions for two light sources to be coherent.

What happens to the interference pattern when two coherent sources are infinitely close?

What happens to the interference pattern when two coherent sources are far apart from each other?

The speed of sound in air is 332 m s⁻¹. Is it advisable to define the length 1 m as the distance travelled by sound in 1/332 s?

Consider Galileo's method of measuring the speed of light using two lanterns. To get an accuracy of about 10%, the time taken by the experimenter in closing or opening the shutter should be about one tenth of the time taken by the light in going from one experimenter to the other. Assume that it takes 1/100 second for an experimenter to close or open the shutter. How far should the two experimenters be to get a 10% accuracy? What are the difficulties in having this separation?

In Fizeau method of measuring the speed of light, the toothed wheel is placed in the focal plane of a converging lens. How would the experiment be affected if the wheel is slightly away from the focal plane?

In the original Fizeau method, the light travelled 8.6 km and then returned. What could be the difficulty if this distance is taken as 8.6 m?

What is the advantage of using a polygonal mirror with larger number of faces in Michelson method of measuring the speed of light?

Light passes through a closed cylindrical tube containing a gas. If the gas is gradually pumped out, the speed of light inside the tube will

The speeds of red light and yellow light are exactly same

An illuminated object is placed on the principal axis of a converging lens so that a real image is formed on the other side of the lens. If the object is shifted a little,

The speed of light is 299, 792, 458 ms⁻¹
(a) with respect to the earth
(b) with respect to the sun
(c) with respect to a train moving on the earth
(d) with respect to a spaceship going in outer space.

Which of the following methods can be used to measure the speed of light in laboratory?

Which of the following methods can be used to measure the speed of light in water?

In an experiment to measure the speed of light by Fizeau's apparatus, following data are used: Distance between the mirrors = 12.0 km,
Number of teeth in the wheel = 180.
Find the minimum angular speed of the wheel for which the image is not seen.