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.
Which of the following representations is correct for an atom X with 28 electrons and 30 neutrons?
\(^{58}_{28}X\)
\(^{30}_{28}X\)
\(^{28}_{30}X\)
\(^{58}_{30}X\)
Correct answer is A
An atom can be represented thus,
\(^{Z}_{A}X\) where Z = mass number
A = atomic number
A = number of proton = number of electrons in a free state = 28
Z = number of protons + number of neutrons = 28 + 30 = 58
\(^{58}_{28}X\)is the representation
30cm3
40cm3
50cm3
20cm3
Correct answer is D
Using boyle's law
P1V1 = P2V2
V2 = \(\frac{P_1 V_1}{200}\) = \(\frac{400 \times 10}{200}\)
= 20cm3
The velocity ratio of an inclined plane where angle of inclination in θ is
Sinθ
Cosθ
Tanθ
\(\frac{1}{\sin \theta}\)
Correct answer is D
Consider an inclined plane shown below, as the effort moves along OB, the load moves is lifted up through a vertical height AB
V.R = \(\frac{\text{distance moved by effort}}{\text{distance moved by load}}\) = \(\frac{OB}{AB}\)
But Sinθ = \(\frac{opp}{hyp}\) = \(\frac{AB}{OB}\)
therefore; = \(\frac{OB}{AB}\) = \(\frac{1}{\sin \theta}\)
Which of the following is not a mechanical wave?
wave in closed pipe
radio waves
water waves
sound waves
Correct answer is B
Mechanical waves require material medium for their propagation only radio waves among the options docs require a material medium
Calculate the time taken for a mango fruit that fall from the tree 20 m to the ground [g = 10 ms-2]
10s
5s
4s
2s
Correct answer is D
u = , H = 20, g = 10
From equation of motion under gravity
H = ut ± \(\frac{1}{2}\)gt2, It is falling so g is +ve
H = 0 + \(\frac{1}{2}\)gt2
H = \(\frac{1}{2}\)gt2
2H = gt2
\(\frac{2H}{g}\) = t2
t = \(\frac{\sqrt{2H}}{g}\)
= \(\frac{\sqrt {2 \times 20}}{10}\)
= √4
= 2s