Physics Questions and Answers

If you want to learn more about the nature and properties of matter and energy or you're simply preparing for a Physics exam, these Physics past questions and answers are ideal for you.

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3,781.

10⁶J of heat is required to boil off completely 2kg of a certain liquid. Neglecting heat lost to the surroundings, the latent heat of vaporization of the liquid is

2.0 x 10⁶J kg^-1

5.0 x 10⁶J kg^-1

2.0 x 10⁵J kg^-1

5.0 x 10⁵J kg^-1

View answer & explanation

Correct answer is D

From the heat exchange involved, the latent heat of vaporization, L can be deduced from the relation:
ML = 10⁶, where M = mass of the liquid.
∴ 2 x L = 10⁶
=> L = ^10⁶/₂ = 5.0 x 10⁵J kg^-1

3,782.

Two liquids L₁ and L₂ are contained in a U - tube. The height and the density of L₁ are 8 cm and 10³ kgm^-3 respectively. If the density of L₂ is 800 kgm^-3, its height measured from the same level is

8 cm

10 cm

16 cm

12 cm

View answer & explanation

Correct answer is B

Generally, from Hares Experiment, density is inversely proportional to height
i.e h ∝1/d; → h₁d₁ = h₂d₂
∴ 8 x 10³ = h₂ x 800

∴ h₂ =	8 x 10³
	_800

= 10cm

3,783.

\( ^{235} _{92}U + ^1 _0n → ^{144} _{56}Ba + ^{90} _{36}Kr +2X \)
In the reaction above, X is

electron

proton

neutrino

neutron

View answer & explanation

Correct answer is D

235U + 1n → 144Ba + 90Kr + 2x9205636
In the reaction above, balancing the left with the right, show that X is neutron

3,784.

In the figure above, the work done by the force of 100N inclined at an angle of 60^o to the object dragged horizontally to a distance of 8m is

800J

600J

100J

400J

View answer & explanation

Correct answer is D

Since the force is inclined at an angle 60^o to the horizontal, the effective component of te force along the horizontal is given by F x cos 60^o
= 100 x 0.5 = 50N.
∴ work done = F x cos 60 x displacement
= 50 x 8.0m
= 400.0J