Work, Energy, and Power — Physics STD 11 Science — Question

When is sum of two vectors always maximum and when is it minimum?

Light from a point source falls on a small area placed perpendicular to the incident light. If the area is rotated about the incident light by an angle of 60°, by what fraction will the illuminance change?

A cubical block of ice floating in water has to support a metal piece weighing 0.5kg. What can be the minimum edge of the block so that it does not sink in water? Specific gravity of ice = 0^.9.

What would be the modulus of elasticity of perfectly elastic substance?

If the force of gravity acts on all bodies in proportion to their masses, then why doesn't a heavy body fall faster than a light body?

What is the time period of oscillation of a pendulum in a satellite?

Two satellites of masses 3m and m orbit the earth in circular orbits of radii r and 3r respectively. What is the ratio of their orbital speeds?

A jeweller put a diamond weighing 5.42g in a box weighing 1.2kg. Find the total weight of the box and the diamond to correct number of significant figures.

A vertical metal cylinder of radius 2cm and length 2m is fixed at the lower end and a load of 100kg is put on it. Find

1. The stress.
2. The strain and.
3. The compression of the cylinder. Young's modulus of the metal = 2 × 10¹¹ N/m².