Light travels -----km per second in air or vacuum.

X-ray and visible light travel at the same speed in vacuum. Do they travel at the same speed in glass?

Light travels fastest in vacuum.Why?

Drow a ray diagram to show a light ray travels from rater medium (air) to denser medium (water)

Two trains leave a railway station at the same time. The first train travelsdue west and the second train due north. The first train travels 5 km/hr faster than second train. If after two hours, they are 50 km apart, find the speed of each train.

Draw a ray diagram to show a light ray travels from denser medium (glass) to raree mediym (air)

Light traveling from a transparent medium to air undergoes that internal reflection at an angle of incident of 45^(@) . Then refractive index of the medium may be

The value of epsilon_(r) for air or vacuum is ........................

Two trains leave a railway station at the same time. The first train travels due west and the second train due north . The first train travels at a speed of 20 km/ hr and the second train travels at 30 km/ hr. After 2 hours, what is the distance between them ?