English Medium कक्षा १० - CBSE Question Bank Solutions for Science

Assertion: On attaining puberty, breast size increases and reproductive organs develop in females.

Reason: Ovaries release the hormone progesterone in females.

The hormone which increases fertility in males is called:

A doctor advised a person to take an injection of insulin because:

Name the gland and the hormone secreted by it in scary situations in human beings. List any two responses shown by our body when this hormone is secreted into the blood.

An object of height 10 cm is placed 25 cm away from the optical centre of a converging lens of focal length 15 cm. Calculate the image distance and height of the image formed.

Name the hormone secreted in scary situations by animals. Write any three responses which enable the animal body to deal with it.

We are advised to take iodised salt in our diet by doctors. Justify its importance in our bodies.

A doctor has advised Sameer to reduce sugar intake in his diet and do regular exercise after checking his blood test reports. Which disease do you think Sameer is suffering from? Name the hormone responsible for this disease and the organ producing the hormone.

What is meant by a power of a lens? Define its SI unit. 

Define the power of a lens.

What does sign of power (+ve or –ve) indicate?

State power of a lens S.I. unit.

How unit of power related to focal length of a lens?

Define 1 dioptre of power of a lens.

 A convex lens forms a real and inverted image of a needle at a distance of 50 cm from it. Where is the needle placed in front of the convex lens if the image is equal to the size of the object? Also, find the power of the lens.

Find the power of a concave lens of focal length 2m.

Find the focal length of a lens of power −2.0 D. What type of lens is this?

A doctor has prescribed a corrective lens of power +1.5 D. Find the focal length of the lens. Is the prescribed lens diverging or converging?