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.
The refractive index of a material is 1.5. Calculate the critical angle at the glass-air interface
19o
21o
39o
42o
Correct answer is D
Sin C = \(\frac{1}{\eta} = \frac{1}{1.5} = 0.6667\)
C = sin\(^{-1}\) 0.6667
= 42°
Images formed by a convex mirror are always
magnified
behind the mirror
real
inverted
Correct answer is B
Convex mirrors always form virtual images, which appear behind the mirror.
at the centre of curvature
at the principal focus
between the pole and principal focus
between the centre of curvature and principal focus
Correct answer is A
No explanation has been provided for this answer.
0.001s
0.010s
10.000s
100.000s
Correct answer is B
Compare: Y = 2 sin 2 \(\pi (\frac{t}{0.01} - \frac{x}{30})\)
with the wave equation,
y = A sin 2 \(\pi (\frac{t}{T} - \frac{x}{\lambda}\))
⇒ \(\frac{t}{T} = \frac{t}{0.01}\)
T = 0.010s
When salt is dissolved in water, the freezing point of the water
increases
decreases
remains the same
increases and later decrease
Correct answer is B
The salt in the water (same for any other impurities) lowers the freezing point of the solution so that water freezes at a lower temperature.