Force, Work, Energy and Power — Physics STD 10 — Question

From α, β and γ-rays, name the one which travels with the speed of light?

(a) In which direction conventional current and electronic current flow from a source of electricity?
(b) Name two materials whose resistance remains the same with the rise in temperature.

Write an expression for calculating electrical power in terms of current and resistance.

State the factor that determine the quality of the note.

Explain why a tight rope-walker, often holds a long pole in his hands when in action.

The marking on an electric bulb reads; 200 V, 60 W. What does it mean?

State expression for Resistance connected in series.

After a robbery, if a window has been broken, there will be tiny particles of glass. Some of these will be found at the scene of the crime and some may be caught in the thief’s clothing. If the police can prove that these particles are identical, they have a strong case.
A method of doing this is to suspend the particles of glass in a special liquid. Light of a single colour is thrown through the liquid and the particles viewed through a microscope. The temperature of the liquid is then slowly altered. This alters the speed of light through the liquid (i.e., it alters the refractive index). At one particular temperature, the particles of glass disappear. It this happens at the same temperature for both sets of glass particles, they probably came from the same broken pane of glass.
Complete and copy the diagram to show how light bends when it travels from the liquid to the glass and back to the liquid, If the light speeds up in the glass.