# Physics Questions for SSC CHSL 2017-18

## Physics Questions for SSC CHSL 2017-18

Q1. The dimension of which of the following is the same as that of impulse?
(a) Volume
(b) Momentum
(c) Torque
(d) Change in the rate of momentum

Q2. Which among the following is the fundamental quantity?
(a) Volume
(b) Time
(c) Velocity
(d) Force

Q3. Who invented Dynamite?
(a) J B Dunlop
(b) Alfred Nobel
(c) James Simons
(d) Peter Hargreaves

Q4. A piece of paper and a cricket ball are dropped from the same height. Under which of the following conditions do both reach the surface simultaneously?
(a) they must have the same volume
(b) they must have the same density
(c) they must have the same mass
(d) they must be dropped in vacuum

Q5. The centre of gravity of a sprinter during the race lies -
(b) behind his feet
(c) at the centre of the body
(d) to the left side of the body

Q6. The Newton’s first law is also called as
(a) law of moments
(b) law of inertia
(c) law of energy
(d) law of momentum

Q7.Why does a Black board appears black in colour?
(a) It reflects black colour
(b) It absorbs black colour
(c) It reflects all colour
(d) It absorbs all colour

Q8. A stone is dropped from the roof of a house towards the ground. The kinetic energy of the stone will be maximum -
(a) just after it is dropped
(b) when it is just on the half-way
(c) just before it touches the ground
(d) when it touches the ground

Q9. The atmospheric air is held to the earth by -
(a) gravity
(b) winds
(c) clouds
(d) rotation of the Earth

Q10. The shape of our Milky way galaxy is -
(a) Circular
(b) Elliptical
(c) Spiral
(d) None of these

Q11. Water boils at a lower temperature on the hills, because
(a) it is cold on the hills
(b) there is less carbon dioxide on the hills
(c) there is decrease in air pressure on the hills
(d) there is less oxygen

Q12. Which of the following is not a vector quantity?
(a) Acceleration
(b) Electric current
(c) Force
(d) Velocity

Q13. Sound cannot pass through -
(a) Water
(b) Steel
(c) Air
(d) Vacuum

Q14.Optical fibre is used in:
(a) CAT scans
(b) X-ray photos
(c) Ultrasound scans
(d) Endoscopy

Q15. Which one of the following animals can hear ultrasonic sound?
(a) Rat
(b) Squirrel
(c) Cat
(d) Bat

S1. Ans.(b)
Sol.Impulse is defined as the integral of a force with respect to time. In other, words the change in momentum is called Impulse, so impulse dimension is equivalent to momentum.
S2. Ans.(b)
Sol. There are 7 basic Fundamental Units- mass(kilogram-kg), length(meter-m), time(second-s), temperature(Kelvin-K), amount of substance(mole- mol), electric current(ampere-A), luminous intensity(candela-cd).
S3. Ans.(b)
Sol.Dynamite is an explosive made of nitroglycerin, sorbents (such as powdered shells or clay) and stabilizers. It was invented by the Swedish chemist and engineer Alfred Nobel in Geesthacht, and patented in 1867. It rapidly gained wide-scale use as a safer alternative to black powder.
S4. Ans.(d)
Sol.In vacuum, both the bodies will reach the ground at the same time. This is because the only acceleration present is earth’s gravity, which points object in downwards direction.
S5. Ans.(a)
Sol.The centre of gravity of a sprinter during the race lies ahead of his feet.
S6. Ans.(b)
Sol.Newton's first law of motion, also known as the law of inertia, states that an object at rest will stay at rest and an object in motion will stay in motion with the same speed and direction unless acted upon by unbalanced force.
S7. Ans.(d)
Sol.A black board appears black because it absorbs all the colors of white light and reflects none.
S8. Ans.(c)
Sol.A stone is dropped from the roof of a house towards the ground. The kinetic energy of the stone will be maximum at just before it touches the ground.
S9. Ans.(a)
Sol.The Earth's atmosphere is an envelope of gas that surrounds the Earth and extends from the Earth's surface out thousands of kilometre. Air in atmosphere is held by earth due to gravity.
S10. Ans.(c)
Sol.There are three main types of galaxies: Elliptical, Spiral, and Irregular. The shape of our Milky way galaxy is spiral.
S11. Ans.(c)
Sol.At hill-stations, the air is generally thinner due to the altitude and the atmospheric pressure is also lower. Here, it requires less than 100 degree celsius temperature to reach the point where the vapor pressure of water reaches that of air. So, water boils below 100°C at hill stations.
S12. Ans.(b)
Sol. Current is not a vector instead of having both magnitude and a direction because a vector always obey the law of addition of vectors. Since current doesn't obey it and it follows algebraic addition, current is a scalar.
S13. Ans.(d)
Sol.Sound cannot travel through a vacuum.
S14. Ans.(d)
Sol.Optical fibre is used in Endoscopy.
S15. Ans.(d)
Sol.Bat use ultrasonic sound for communication and navigation.
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