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.
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.
thermionic emission
nuclear fission
thermonuclear fusion
photoelectric emission
Correct answer is C
Thermonuclear fusion is the process that occurs when two atoms combine to make a larger atom, creating a whole lot of energy. Fusion already happens naturally in stars — including the sun — when intense pressure and heat fuse hydrogen atoms together, generating helium and energy.
Thermionic emission: thermally induced flow of charge
Nuclear fission: nuclear reaction or a radioactive decay process
Photoelectric emission: emission of electrons or other free carriers when light shines on a material
Transitional Motion
Rotational Motion
Brownian Motion
Oscillatory Motion
Correct answer is C
Brownian motion, also called Brownian movement, any of various physical phenomena in which some quantity is constantly undergoing small, random fluctuations.
If a number of particles subject to Brownian motion are present in a given medium and there is no preferred direction for the random oscillations, then over a period of time the particles will tend to be spread evenly throughout the medium.
33\(^o\)c
40\(^o\)c
25\(^o\)c
10\(^o\)c
Correct answer is A
Water 1 => M = 150g = 0.15kg,
θ\(_2\) = 60\(^o\)C; θ\(_1\) = θ
Q\(_1\) = MC (θ\(_2\) – θ\(_1\))
= 0.15C (60 - θ)
Water 2 => M = 300g = 0.3kg
θ1 = 20\(^o\)C, θ\(_2\) = θ
Q2 = MC (θ\(_2\) – θ\(_1\))
= 0.3C (θ – 20)
Combining Q1 and Q2
0.15C (60 - θ) = 0.3C (θ – 20)
9 – 0.15θ = 0.3θ – 6
0.3θ + 0.15θ = 9 + 6
0.45 θ = 15
θ = 33.33\(^o\)C
Mercury which is spilled onto a glass surface forms ball-like shapes because____.
Mercury is a metal
The cohesive force between its molecules is greater than the adhesive force between mercury and glass molecules
The cohesive force between its molecules is less than the adhesive force between mercury and glass molecules
The viscosity of mercury is height
Correct answer is B
In case of small drops of mercury, the gravitational potential energy is negligible in comparison to the potential energy due to surface tension.Consequently, to keep the drop in equilibrium, the mercury drop’s surface tends to contract so that its surface area will be the least for a sphere and the drops will be spherical.
But in the case of bigger drops of mercury, the potential energy due to gravity is predominant over the potential energy due to surface tension.Consequently, to keep equilibrium , the mercury drop tends to assume minimum potential energy as possible, the drop becomes oval in shape and lower center of gravity.
A 40W instrument has a resistance 90 Ohms. On what voltage should it be operated normally
60V
150V
225V
360V
Correct answer is A
P = 40W
R = 90W
V = ?
P = \(\frac{V^2}{R}\)
V\(^2\) = PR = 40 x 90
V\(^2\) = 3000
V = √3600
V = 60N