Machines — Physics STD 10 — Question

A body is acted upon by two force of magnitude F, but in opposite directions. State the effect of the force if

the two forces act at two different points of the body at a separation r.

Write the approximate wavelengths for (i) blue and (ii) red light.

Some heat is provided to a body to raise its temperature by 25°C. What will be the corresponding rise in temperature of the body as shown on the Kelvin scale?

Energy can exist in several forms and may change from one form to another. For the following, state the energy changes that occur in:
explosion of crackers.

Does the substance absorb or liberate any heat energy during the change of phase?

Energy can exist in several forms and may change from one form to another. For the following, state the energy changes that occur in:
the unwinding of a watch spring

State whether a solar cell produces a.c. or d.c.

What is Lenz's law?

Name two factors on which the heat absorbed or given out by a body depends.

An electrons emitter must have how much work function and melting point.