Class 11th

The species which does not exist is

Which among the following species is pyramidal in shape?

If the distance between successive compressions and rarefaction in a sound wave is 2 m and velocity of sound is 360 m/s, then the frequency is

The radii of circular orbits of two satellites A and B of the earth, are 4R and R, respectively. If speed of satellite A is 2V, then the speed of satellite B will be

The angular frequency of a simple pendulum is Ω rad/s. Now the length is made one fourth of the original length, the angular frequency becomes

A body of mass M is rotating in a vertical circle of radius r with critical speed. The difference in its kinetic energy at the top and the bottom is

Two trains 101 m and 99 m in length are running in opposite direction with velocities 54 km/h and 36 km/h. In what time they will completely cross each other?

A 0.8 m long solenoid has 800 turns and has a field density of 2.52 * 10^–3 T at its centre. What is current in the wire?

A positive charge is moved from low potential point A to a high potential point B. Then the electric potential energy

Two waves of wavelength 50 cm and 51 cm produced 12 beats per second. The velocity of sound is