## Eating food during Eclipse

I heard that we ought not eat anything in eclipse hours. Is there any scientific reason for that?

There is no scientific reason behind it. Earlier it was thought that more harmful

## CBSE 12th Std Physics Numerical from Optics

A convex lens of crown glass(1.5) has a focal length of 15 cm. The lens is placed in (a) water(1.33) and carbon bisulphide(1,65).determine in each case whether the lens behaves as a conveging or a diverging

## CBSE Physics MCQ for quick revision – Mechanics

• If the object is in equilibrium, the sum of all the forces acting on the object is zero.
1. Inertia
2. Force
3. Mechanical Equilibrium
4. Equilibrium rule

• A push or a pull on an

## Class XI CBSE – Revision Questions MCQ – Semester 1

1. What is the gravitational field strength of a planet when the weight of a 100 kg astronaut is 400 N?

a)      ¼ N kg-1   b) 9.8 N kg-1 c) 4 N kg-1  d) infinity

1. The only natural satellite of the earth complete orbits in about

a)      24 days b) 27.3 days c) 30 days d) 365 1/4 days

1. The satellite that revolves in a polar orbit is called

a) Natural Satellite b) Geostationary satellite   c) Polar

## Motion of connected system – A Numerical problem

A mass 5kg descending vertically,draws up a mass of3kg by means of a light string passing over a pulley.At the end of 4 seconds,the string breaks.How much higher 3 kg mass would go?