Refraction through Lenses and Optical Instruments — Physics STD 10 — Question

50 g of metal piece at 27°C requires 2400 J of heat energy so as to attain a temperature of 327°C . Calculate the specific heat capacity of the metal.

A person standing between two vertical cliffs produces a sound. Two successive echoes are heard at 4 s and 6 s. Calculate the distance between the cliffs.

Explain, why is water used as a coolent in motor car radiators?

Define the optical centre of a lens.

A boy takes 3 minutes to lift a 20 litre water bucket from a 20 m deep well, while his father does it in 2 minutes. compare :
(i) the work, and
(ii) power developed by them.

State the effects that a force can produce. Given one example of each.

The diagram shows a uniform metre rule weighing 100gf, pivoted at its centre O. Two weights 150gf and 250gf hang from the point A and B respectively of the metre rule such that OA = 40 cm and OB = 20 cm. Calculate :

the distance from O where a 100gf weight should be placed to balance the metre rule.

Calculate the decrease in the kinetic energy of a moving body if its velocity reduces to half of the initial velocity.

A uniform circular motion is an accelerated motion explain it. State whether the acceleration is uniform or variable? Name the force responsible to cause this acceleration. What is the direction of force at any instant? Draw diagram in support of your answer.