| 141. | Why does water boil at a temperature below 100°C at high altitudes? |
A. As the atmospheric pressure decreases, so the boiling point comes down | |
B. Because gravity is less | |
C. High winds in the mountains | |
D. None of the above |
| 142. | pressure inside the soap bubble |
A. Exceeds atmospheric pressure | |
B. Is less than atmospheric pressure | |
C. Is equal to atmospheric pressure | |
D. Is half of atmospheric pressure |
| 143. | why do we slip on muddy roads |
A. Gravitational force | |
B. Relative velocity | |
C. Lack of friction | |
D. Excess of friction |
| 144. | When the temperature of the barometer suddenly falls, what does it indicate? |
A. Hot weather | |
B. Chilly weather | |
C. Chance of thunderstorms | |
D. Dry weather |
| 145. | A balloon of polythene filled with hydrogen is released from the ground of the earth on rising to the height of the atmosphere- |
A. The size of the balloon will decrease | |
B. The balloon will flatten into a circular shape | |
C. The size of the balloon will increase | |
D. The size and shape of the balloon will remain the same as before |
| 146. | Why is it harder to breathe on the mountains than on the plains? |
A. Air pressure decreases with increase in altitude and the need for oxygen increases. | |
B. Mountain air is heavy and cannot be filled with lungs | |
C. Mountain air is impure, so we cannot take | |
D. None of the above |
| 147. | When the Fortine barometer is taken to a high mountain, the mercury in the tube falls because- |
A. The air is lighter there | |
B. The temperature drops with the decrease in temperature | |
C. There the atmospheric pressure becomes lower | |
D. There the surface tension decreases |
| 148. | Before flight, the airplane is run on the runway- |
A. To reduce working air pressure | |
B. To increase working air pressure | |
C. To reduce the force of friction between the ground by air pressure | |
D. To increase the force of friction between the ground by air pressure |
| 149. | A rubber balloon filled with hydrogen bursts on rising in the air because- |
A. Hydrogen content increases | |
B. Air pressure rises | |
C. Hydrogen pressure drops | |
D. Air pressure drops |
| 150. | Why food cooks in less time in pressure cooker |
A. The temperature of boiling water decreases due to high pressure | |
B. Air is not affected due to being closed from all sides; Air is not affected due to being closed from all sides | |
C. High pressure increases the temperature of boiling water | |
D. Evaporation of water used is very less |