Human Eye and Colourful World — Science STD 10 — Question

Draw ray diagrams showing the image formation by a concave lens when an object is placed:
Beyond twice the focal length of the lens.

An electric kettle rated at 220V, 2.2kW, works for 3 hours. Find the energy consumed and the current drawn.

How is the reflection of light ray from a plane mirror different from the refraction of light ray as it enters a block of glass?

Draw ray diagrams showing the image formation by a concave mirror when an object is placed:
At centre of curvature of the mirror.

How does the thickness of the eye lens change when we shift looking from a distant tree to reading a book?

Classify the following into good conductors, resistors and insulators:
Rubber, Mercury, Nichrome, Polythene, Aluminium, Wood, Manganin, Bakelite, Iron, Paper, Thermocol, Metal coin.

Identify the device used as a spherical mirror or lens in following cases, when the image formed is virtual and erect in each case.

Object is placed between the focus and device, image formed is enlarged and on the same side as that of the object.

To construct ray diagram we use two light rays which are so chosen that it is easy to know their directions after reflection from the mirror. List these two rays and state the path of these rays after reflection. Use these rays to locate the image of an object placed between centres of curvature and focus of a concave mirror.

Draw ray diagrams showing the image formation by a convex lens when an object is placed:

At twice the focal length of the lens.