Physics Questions

The objects through which light cannot pass are called as Opaque objects. Some objects allow some light to pass through them and are called as Translucent objects. The objects which allow all the light to pass through them are called as Transparent objects.

Here in the given options Book is an example of opaque object as it does not allow light to pass through it. Water is transparent object and notebook paper and sun glasses are examples of translucent objects.

In vacuum and in homogeneous, transparent media, such as air, water, and glass, light moves in a straight line. When light encounters a boundary between two different transparent media, some light is reflected and some moves from the first into the second medium.

The Cartesian Coordinates can be retrieved from spherical coordinates (l,q,a) by:

X = r.sinq.cosa

Y = r.sinq.sina

Z = r.sinq

Using the same we get for P,

Y = P.sinq.sina

Electric power is the rate per unit time, at which electrical energy is transferred by an electric circuit. The power of electricity is measured in watts and kilo watts.

1 Watt is the unit of electrical power equal to one ampere under the pressure of one volt.

Materials that usually allow electricity to pass through them are called Good conductors of electricity.

Conductors conduct electrical current very easily because of their free electrons.

Examples are :: Aluminium, Gold, Copper, Silver

Materials that do not allow or oppose electrical current & make poor conductors are called Insulators.

Examples are :: Glass, Plastic, Wood, Air,...