A fresh egg sinks in pure water, whereas it floats in saturated salty water. This is due to

1. 1. Higher density of the salty water
   2. the fluid matter inside the egg-shell
   3. the fact that the egg-shell is made of calcium which is heavier than pure water
   4. Higher density of the pure water

A mixture of which of the following gases is used in the manufacture of electric bulbs?

1. 1. Nitrogen and Oxygen
   2. Oxygen and Argon
   3. Oxygen and Hydrogen
   4. Nitrogen and Argon

Why are transformer used in the transmission of electric power?

1. 1. Because they can conserve electrical energy
   2. Because they help to distribute electrical energy efficiently
   3. Because they speed up transmission
   4. because they can reduce transmission losses

a magnet freely suspended by means of a string will always set itself in which of the directions?

1. 1. For guarding the instruments against unauthorized handling
   2. For protection against the effect of external magnetic fields
   3. For absorbing heat generated during the functioning of the instrument
   4. For protection against the effect of moisture in the air

In the modern-day computers, when operational, the electrical impulses travel _____.

1. 1. At half the speed of light
   2. At the speed of sound
   3. At seven times the speed of sound
   4. Nearly at the speed of light

In a photographic camera fitted with a convex lens, which of the following types of images will be formed on the film?

1. 1. Imaginary and erect
   2. Erect and real
   3. Inverted and real
   4. The type of image formed will depend on the distance between the lens and the object

Echo is the effect produced due to _____.

1. 1. Reflection of sound
   2. Absorption of sound
   3. Refraction of sound
   4. Dispersion of sound

The speed of sound is maximum through which of the following?

1. 1. Water
   2. Wood
   3. Air
   4. Glass

Why does water biol below 100°C at higher altitudes?

1. 1. Water available at higher altitudes is purer than that in the plains
   2. There is lesser dissipation of heat at higher altitudes
   3. The atmospheric pressure at higher altitudes is low compared to that at sea level
   4. Pollution free air at higher altitudes increases the calorific value of fuel used

Why does the mercury column in the barometer fall rapidly before a severe strom?

1. 1. It is due to the fall in atmospheric pressure
   2. It is due to the severe heat energy from the sun
   3. It is due to decrease in humidity in air
   4. It is due to the rise in atmospheric