Physics

Total internal reflection occurs when light travels from:

Calculate the refractive index of a medium if the speed of light in that medium is 2 x 10^8 m/s.

An object is placed 10 cm in front of a concave mirror of focal length 15 cm. The image formed is:

What is the power of a combination of two lenses with powers +2D and -1D in contact?

A ray of light is incident on a glass slab. If the angle of incidence is 45 degrees and the angle of refraction is 30 degrees, what is the refractive index?

Where should an object be placed in front of a convex lens to get a real image of the same size?

If the critical angle for a medium is 45 degrees, what is its refractive index?

What is the focal length of a lens with power -4.0 D?

A student sitting on the last bench cannot read the writing on the blackboard clearly. Which defect of vision is he suffering from?

In which medium does light travel the fastest?

If the magnification of a lens is -0.5, the image is:

The phenomenon used in optical fibers to transmit signals is:

What happens to the focal length of a convex lens when it is immersed in water?

A point source of light is placed at the focus of a convex lens. The emerging rays will be:

If the image distance (v) is 20 cm and object distance (u) is -10 cm for a lens, what is the magnification?

Which defect of vision occurs due to the gradual weakening of ciliary muscles in old age?

A ray of light passes through the optical center of a thin lens. What is its path?

Calculate the focal length of a convex lens which forms a real image at 20 cm when an object is placed 20 cm away.

What is the cause of 'Twinkling of Stars'?

In a periscope, the two plane mirrors are placed: