State Of Matter

Total Questions: 27

1. When iron rusts, its weight _____ . [S.S.C. Online Graduation Level (T-I) 7.09.2016 (Shift-I)]

(a) decreases
(b) increases
(c) remains the same
(d) first increases and then decreases

Correct Answer: (b) increases

Solution:When rusting, the weight of iron increases.

Rusting is a chemical reaction between iron (Fe), oxygen (O₂), and moisture (H₂O), forming iron oxide (Fe₂O₃·xH₂O) — commonly known as rust.

In this process:

Oxygen from the air combines with iron.
Since oxygen atoms are added, the total mass increases.

2. The unit of which physical quantity is not pascal? [S.S.C. Online CHSL (T-I) 18.01.2017 (Shift-I)]

(a) Moment of Inertia
(b) Pressure
(c) Stress
(d) Young's Modulus

Correct Answer: (a) Moment of Inertia

Solution:The unit of moment of inertia is kg.m², and the dimension is [ML²].

The property of a body due to which it opposes the change in rotation about an axis is called the moment of inertia of the body about the axis of rotation.

The unit for all other quantities in options is 'Pascal'.

3. What is the SI unit for measuring pressure? [S.S.C. Online CHSL (T-I) 4.08.2021 (Shift-I)]

(a) Ampere
(b) Candela
(c) Kelvin
(d) Pascal

Correct Answer: (d) Pascal

Solution:The SI unit for measuring pressure is the pascal (Pa).
Here's a little more detail:
Pascal (Pa):
It's defined as one newton per square meter (N/m²).
This means it measures the force exerted over a unit area.

While other units of pressure exist (like bar, psi, and atm), the pascal is the standard unit used in the International System of Units (SI).

4. What is the unit of the physical quantity "Young's Modulus"? [S.S.C. Online CHSL (T-I) 8.02.2017 (Shift-III)]

(a) Newton
(b) Erg
(c) Joule
(d) Pascal

Correct Answer: (d) Pascal

Solution:Young's modulus is a measure of a material's stiffness.
Therefore, its unit is the same as the unit of stress.
Here's a breakdown
The SI unit of Young's modulus is the pascal (Pa).
Since pascal is equivalent to newtons per square meter (N/m²).

5. The instrument used for measuring air pressure is called ________ . [S.S.C. Online Graduation Level (T-I) 7.09.2016 (Shift-I)]

(a) Anemometer
(b) Barometer
(c) Hygrometer
(d) Thermometer

Correct Answer: (b) Barometer

Solution:A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.

6. Which of the following scientific instruments is used to measure atmospheric pressure? [S.S.C. JE Electrical Exam 27.10.2020 (Shift-II) S.S.C. Online CHSL (T-I) 19.01.2017 (Shift-I)]

(a) Audiometer
(b) Odometer
(c) Seismograph
(d) Barometer

Correct Answer: (d) Barometer

Solution:A barometer is a scientific instrument used to measure atmospheric pressure, also called barometric pressure.

7. A sudden fall in the barometric reading is an indication of ________ . [S.S.C. Online CHSL (T-I) 16.01.2017 (Shift-I)]

(a) Storm
(b) Scorching heat
(c) Rain
(d) Clear weather

Correct Answer: (a) Storm

Solution:A sudden fall in the barometric reading is an indication of :
Stormy weather.
Atmospheric pressure is closely linked to weather patterns.
A sudden drop in pressure signifies that an area of low pressure is approaching.
Low-pressure systems are often associated with unsettled weather, including storms, rain, and strong winds.

8. Skating on the ice shows that the increase in pressure ________ melting point of ice. [S.S.C. Online Stenographer 13.09.2017 (Shift-II)]

(a) Decreases
(b) Increases
(c) First decreases then increase
(d) Remains unchanged

Correct Answer: (a) Decreases

Solution:The skaters slide more easily on ice than on other smooth surfaces because ice melts under pressure exerted by the skates to produce a thin film of water.

Hence, it is true that an increase in pressure will result in decreasing the melting point.

9. Calculate the pressure (in Pa) if a thrust of 800 N is applied to an area of 16 m². [S.S.C. Online CHSL (T-I) 7.03.2018 (Shift-II)]

(a) 128
(b) 100
(c) 64
(d) 50

Correct Answer: (d) 50

Solution:Pressure = (force) / (area)
= 800 / 16 = 50 N/m²
We know that
1 N/m² = 1 pa (Pascal)
So pressure = 50 (Pa)

10. What do you divide thrust in a liquid to obtain the pressure value? [S.S.C. Online CGL (T-I) 13.08.2021 (Shift-II)]

(a) Volume
(b) Density
(c) Area
(d) Mass

Correct Answer: (c) Area

Solution:Thrust is the force acting perpendicular to the surface of an object.
Therefore, pressure force / area, so it is clear that thrust is divided by area to get pressure.
The SI unit of pressure is Newton/m² or Pascal.

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