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

A source of sounds is travelling with a velocity of 40 km/hr towards an observer and emits sound of frequency 2000 Hz. If the velocity of sound is 1220 km/hr, then what is the apparent frequency heard by the observer?

A unit vector is used to specify –

Non conservative force is

One horse power (1 hp) is

A gale blows over a house. The force due to the gale on the roof is ………

The internal energy of an ideal gas depends on

Two quantities A and B have different dimensions. Which of the following is physically meaningful?

A container contains hydrogen gas at pressure P and temperature T. Another identical container contains helium gas at pressure 2P and temperature T/2. The ratio of the number of molecules of the two gases is

The error caused due to the shear carelessness of an observer is called as …… error.

The direction of torque is found using –