our environment — Science STD 10 — Question

Define: Family of salts

For which colour has the glass larger refractive index-violet or green?

State the function of the iris.

Which causes more bending (or more refraction) of light rays passing through it: a convex lens of long focal length or a convex lens of short focal length?

State the chemical equation for the process of photosynthesis.

Identify me: A component of gastric juice protect the inner lining of the stomach from the action of hydrochloric acid under normal condition.

Name the following:
A point inside a lens through which the light passes undeviated.

Which has more power: a thick convex lens or a thin convex lens made of the same material (glass)? Give reason for your choice.

Identify the device used as a spherical mirror or lens in the following cases, when the image formed is virtual and erect in each case.
(1) An object is placed between the device and its principal focus. The image formed is enlarged and behind the device.
(2) The object is placed between the principal focus and device. The image formed is enlarged and on the same side as that of the object.
(3) The object is placed at finite distance from the device (i.e., between infinity and device). The image formed is diminished and lies between the principal focus and optical centre and on the same side as that of the object.
(4) The object is placed at finite distance from the device (i.e., between infinity and device). The image formed is diminished and lies between the pole and principal focus as well as behind it.