Nature of Physical World and Measurement — Physics STD 11 — Question

The angle between anti parallel vectors is –

The frequency of a radar is 780 MHz. When it is reflected from an approaching aeroplane the opponent frequency is more than the actual frequency by 2.6 kHz. The speed of the aeroplane is ……

For a given momentum, the kinetic energy is proportional to

The molecular weights of oxygen and hydrogen are 32 and 2, respectively. The rms velocities of their molecules at a given temperatures, will be in the ratio

The frequency of a sound wave is/and its velocity is v. If the frequency is increased to 4 f the velocity of the wave will be:

For rotational motion, moment of inertia is a measure of –

Sliding of the object occurs when –

A car covers half of its journey with a speed of 10 ms-1 and the other half by 20 ms-1. The average speed of car during the total journey is –

The escape velocity of a body on the surface of the Earth is 11.2 km/s. If the mass of the Earth is increase to twice its present value and the radius of the earth becomes half, the escape velocity becomes = …… kms-1