Pressure in Fluids Class-9 Exe-4B MCQs Concise Physics ICSE Selina Solutions Ch-4. In this article you would learn to solve MCQs on Atmospheric Pressure and it’s Measurement. Visit official Website CISCE for detail information about ICSE Board Class-9 Physics.
Pressure in Fluids Class-9 Exe-4B MCQs Concise Physics ICSE Selina Solutions Ch-4
| Board | ICSE |
| Class | 9th |
| Subject | Physics |
| Writer / Publication | Concise Selina Publishers |
| Chapter-4 | Pressure in Fluids and Atmospheric Pressure |
| Exe – 4B | Atmospheric Pressure and it’s Measurement |
| Topics | Solution of Exe-4(B) MCQs Type |
| Academic Session | 2025-2026 |
Atmospheric Pressure and it’s Measurement
Pressure in Fluids Class-9 Exe-4B MCQs Concise Physics ICSE Selina Solutions Ch-4
Page 111 (Choose the correct answer from the options given below).
Que-1: The thrust exerted per unit area on the earth’s surface due to a column of air is called :
(a) pressure
(b) atmospheric pressure
(c) density
(d) buoyancy
Ans: (b) atmospheric pressure
Hint- The thrust exerted per unit area on the earth’s surface due to column of air, is called atmospheric pressure on the surface of earth.
Que-2: The normal atmospheric pressure is :
(a) 76 m of Hg
(b) 76 cm of Hg
(c) 76 Pa
(d) 76 N m-2
Ans: (b) 76 cm of Hg
Hint- As we know that, barometric height at normal temperature and pressure at sea level is 76 cm of Hg and barometric height is the measure of the atmospheric pressure. Hence, normal atmospheric pressure = 76 cm of Hg.
Que-3: The unit torr is related to the barometric height as:
(a) 1 torr = 1 cm of Hg
(b) 1 torr = 0.76 cm of Hg
(c) 1 torr = 1 mm of Hg
(d) 1 torr = 1 m of Hg
Ans: (c) 1 torr = 1 mm of Hg
Hint- torr is a unit of atmospheric pressure after the name of the scientist Torricelli where, 1 torr = 1 mm of Hg.
Que-4: The atmospheric pressure at earth surface is P1 and inside mine is P2. They are related as:
(a) P1 = P2
(b) P1 > P2
(c) P1 < P2
(d) P2 = 0
Ans: (c) P1 < P2
Hint- Atmospheric pressure increases with depth. Hence, P1 < P2.
Que-5: Nose bleeding occurs at high altitude because:
(a) the blood pressure become less than the atmospheric pressure
(b) the blood pressure become equal to the atmospheric pressure
(c) the blood pressure more than the atmospheric pressure
(d) not related with atmospheric pressure
Ans: (c) the blood pressure more than the atmospheric pressure
Hint- Nose bleeding occurs at high altitude because the blood pressure more than the atmospheric pressure.
Que-6: Simple barometer was first designed by :
(a) Sir Issac Newton
(b) Pascal
(c) Torricelli
(d) Thomas Alva Edison
Ans: (c) Torricelli
Hint- In 1643, Torricelli first designed a simple barometer using mercury as the barometric liquid.
Que-7: A barometer is used :
(a) to measure atmospheric pressure
(b) for weather forecasting
(c) as an altimeter to measure heights
(d) all of the above
Ans: (d) all of the above
Hint- Measuring atmospheric pressure, weather forecasting, measuring heights, all these are valid uses of a barometer.
Que-8: At the summit of Mount Everest, the atmospheric pressure is :
(a) only 40% of the atmospheric pressure at sea level
(b) only 60% of the atmospheric pressure at sea level
(c) only 30% of the atmospheric pressure at sea level
(d) only 50% of the atmospheric pressure at sea level
Ans: (c) only 30% of the atmospheric pressure at sea level
Hint- At the summit of Mount Everest, the atmospheric pressure is only 30% of the atmospheric pressure at sea level.
Page 112
Que-9: At high altitude, the atmospheric pressure is :
(a) less
(b) high
(c) high due to strong winds
(d) low due to the cloud
Ans: (a) less
Que-10: Mercury is preferred as a barometric liquid because :
(a) its density is high
(b) its vapour pressure is negligible
(c) it neither wets nor sticks to the glass
(d) all of the above
Ans: (d) all of the above
Hint- Uses of mercury as a barometric liquid are —
The density of mercury is greater than that of any liquid, so only 0.76 m of height of mercury is needed to balance the normal atmospheric pressure. Use of other liquids will require a much longer tube.
The vapour pressure of mercury is negligible, so the vapours in the torricellian vacuum does not affect the barometric height.
Mercury neither wets nor sticks to the glass tube, therefore it gives accurate reading.
Que-11: Which of the following properties of water is incorrect regarding its non-usage as a barometric liquid?
(a) It neither wets nor sticks to the glass tube
(b) The vapour pressure of water is high
(c) The surface of water cannot be easily seen while taking observations
(d) The density of water is low.
Ans: (a) It neither wets nor sticks to the glass tube
Hint- Water sticks to the glass tube and wets it, so the reading becomes inaccurate.
Que-12: If the barometric height gradually falls, it indicates :
(a) a possibility of a storm or cyclone
(e) extremely dry weather
(c) weather will remain the same.
(d) a possibility of rain.
Ans: (d) a possibility of rain.
Hint- If the barometric height gradually falls, it indicates that the moisture is increasing i.e., there is a possibility of rain.
Que-13: The atmospheric pressure …………… with rising altitudes as the density of air …………… .
(a) increases, decreases
(b) decreases, increases
(c) decreases, decreases
(d) increases, increases
Ans: (c) decreases, decreases
Hint- Atmospheric pressure decreases with altitude due to (1) decrease in height of air column, (2) decrease in density of air.
Que-14: Altimeter is used in an aircraft to measure :
(a) atmospheric pressure
(b) altitudes
(c) speed
(d) distance travelled
Ans: (b) altitudes
Hint- An altimeter is an aneroid barometer, and it is used in aircraft to measure it’s altitude.
— : End of Pressure in Fluids Class-9 Exe-4B MCQs Concise Physics ICSE Selina Solutions Ch-4. :–
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