Chemical Reactions and Equations — Science STD 10 — Question

A coil is connected to a galvanometer. When the N-pole of magnet is pushed into the coil, the galvanometer deflected to the right. What deflection, if any, is observed when:

1. The N-pole is removed?
2. The S-pole is inserted?
3. The magnet is a rest in the coil?

An electric lamp of 100 Ω, a toaster of resistance 50 Ω, and a water filter of resistance 500 Ω are connected in parallel to a 220 V source. What is the resistance of an electric iron connected to the same source that takes as much current as all three appliances, and what is the current through it?

The near point of the eye of a person is 50cm. Find the nature and power of the corrective lens required by the person to enable him to see clearly the objects placed at 25cm. from the eye.

State the differences between artery, vein and capillary.

Consider the circuit given below where A, B and C are three identical light bulbs of constant resistance.

1. List the bulbs in order of increasing brightness.
2. If C burns out, what will be the brightness of A now compared with before?
3. If B burns out instead, what will be the brightness of A and C compared with before?

What is meant by the terms ‘single circulation’ and ‘double circulation’?

In which form is the 10% energy available for transfer?

A lens of focal length 20cm is used to produce a ten times magnified image of a film slide on a screen. How far must the slide be placed from the lens ?

Explain why, the planets do not twinkle at night?

What are sexually transmitted diseases. List two example of each diseases caused due to,

1. Bacterial infection.
2. Viral infection.

Which device or devices may be used to prevent the spread of such diseases.