Machines — Physics STD 10 — Question

What type of lever is formed by the human body while raising the weight of body on toes?

(a) Give a list of at least five radiations, in order of their increasing frequencies, which make up the complete electromagnetic spectrum.

(b) Which of the radiation mentioned by you in part (a) has the highest penetrating power.

Write down the Einstein's mass-energy equivalence relation, explaining the meaning of each symbol used in it.

How is the mechanical advantage related with the velocity ratio for an actual machine? State whether the efficiency of such a machine is equal to 1, less than 1 or more than 1.

What change do you expect in the characteristics of a musical sound if
(i) Its frequency is increased,
(ii) Its amplitude is increased?

What is the cause of refraction of light?

A bucket contains 10 liters of water at 80°C. Cold water at 25°C is run from a tap into the bucket of hot water for 20 seconds and the temp. Of the water in the bucket falls to 50°C.
(a) Calculate the rate at which cold water came out of the tap.
(b) State an assumption made in the above calculation.

Name and define the characteristic which enables one to distinguish two sounds of same loudness, but of different frequencies, given by the same instrument.