Which of the following statements about the universal gravitational constant, G, is true?
It is fundamental quantity
It has dimension M-¹L³T-²
Its S.I. unit is N m\(^2\)kg
It is a vector quantity
Correct answer is B
The universal Gravitational constant(G) is a scalar quantity as it is not in a particular direction.
dimensional formula =M-¹L³T-²
S.I. unit = Nm\(^2\)/kg\(^2\)
A current of 2A passes through a wire of resistance 4Ω for 3 minutes. Calculate the energy lost
960J
1440J
2880J
48J
Correct answer is C
Power = current[I]\(^2\) * Resistance[R] → 2\(^2\) * 4 → 4 * 4 = 16watts
time = 3minutes → 3 * 60 = 180s
Energy = power * time → 16 * 180 = 2880j
The diagram above is an illustration of an a.c. circuit.Calculate the reactance of the capacitor.
2016Ω
2000Ω
200Ω
4000Ω
Correct answer is C
Capacitive reactance, X\(_C\) = \(\frac{1}{2πFC}\) → \(\frac{1}{2π * 500/π * 5 * 10^{-6}}\)
= \(\frac{1}{0.005}\) → 200Ω
Which of the following statements is an effect of compressing gas molecules at constant temperature?
The pressure on the molecules decreases.
The molecules gain more kinetic energy
The molecules make more impact per second on the walls of the container
The molecules increase in size
Correct answer is C
More collisions mean more force, so the pressure will increase.
When the volume decreases, the pressure increases.
This shows that the pressure of a gas is inversely proportional to its volume.
This is shown by Boyle's law.
A ball is swung in a horizontal circle of centre O with a constant speed. acceleration?
Away from O
Along the Circumference of the circle
Toward centre O
Along a tangent to the circle
Correct answer is C
Simple harmonic motion (SHM) is a special type of periodic motion where the restoring force on the moving object is directly proportional to the magnitude of the object's displacement and acts towards the object's equilibrium position.
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