Reaching the Age of Adolescence — Science STD 8 — Question

What change in the voice of body takes place when they reach puberty? What is the cause of this change?

How do viruses differ from other microorganisms, such as bacteria?

What are oviparous animals? Give two examples of oviparous animals.

What is noise? Give two examples of sounds which are considered noise.

An archer stretches her bow while taking aim at the target. She then releases the arrow, which begins to move towards the target. Based on this information, fill up the gaps in the following statements using the following terms: muscular, contact, non-contact, gravity, friction, shape, attraction
(a) To stretch the bow, the archer applies a force that causes a change in its ____________ .
(b) The force applied by the archer to stretch the bow is an example of ____________ force.
(c) The type of responsible for a change in the state of motion of the arrow is an example of a ____________ force.
(d) While the arrow moves towards its target, the forces acting on it are due to ____________ and that due to ____________ of air.

A Voltaic cell, also known as a Galvanic cell, contains two metal plates made of different materials and a liquid called an electrolyte, placed in a glass or plastic container. The plates, called electrodes, are partly dipped in the electrolyte, which is usually a weak acid or a salt solution. A chemical reaction between the plates and the electrolyte produces electricity.
(a) In what way is the Voltaic cell different from the dry cell?
(b) Who discovered the Voltaic or the Galvanic cell? What was the difference of opinion between the two scientists about the electricity generation by the cell, and how was it resolved?

Which state of matter has the highest kinetic energy?

Mention the reason that brings the sound of fire crackers to our ears.

Which lens diverges the light ray?

Give reason why: Graphite is used for making electrode in a cell.