GCE Advanced Level — Physics Quiz

Q1
In a common-emitter transistor circuit, the supply voltage is $V_{CC} = 12.0\,\text{V}$ and the collector resistor is $R_C = 1.0\,\text{k}\Omega$ . The transistor has a current gain $\beta = 100$ and a base-emitter voltage $V_{BE} = 0.7\,\text{V}$ when conducting. If the base resistor is $R_B = 200\,\text{k}\Omega$ and the input voltage to the base resistor is $5.7\,\text{V}$ , what is the collector-emitter voltage $V_{CE}$ ?
$0.2\,\text{V}$
$2.5\,\text{V}$
$5.0\,\text{V}$
$9.5\,\text{V}$
$12.0\,\text{V}$
Q2
A circular metal disc of radius $0.20 \,\text{m}$ rotates at $100 \,\text{rev s}^{-1}$ about an axis passing through its center and perpendicular to its plane. A uniform magnetic field of $0.05 \,\text{T}$ is applied parallel to the axis. What is the potential difference between the center and the rim of the disc?
$0.02 \pi \,\text{V}$
$0.1 \pi \,\text{V}$
$0.2 \pi \,\text{V}$
$0.4 \pi \,\text{V}$
$2.0 \pi \,\text{V}$
Q3
Which of the following statements about sound waves propagating in air is correct?
The particles of air oscillate in a direction perpendicular to the direction of wave propagation.
The distance between a compression and the adjacent rarefaction is equal to one wavelength.
The speed of sound in air is independent of the temperature of the air.
The pressure of the air is maximum at the center of a compression.
Sound waves can be polarized using a suitable filter.
Q4
A person of mass $60\,\text{kg}$ is in an elevator accelerating upwards at $2.0\,\text{m s}^{-2}$ . The apparent weight of the person is (take $g = 10\,\text{m s}^{-2}$ ):
$480\,\text{N}$
$600\,\text{N}$
$720\,\text{N}$
$840\,\text{N}$
$1200\,\text{N}$
Q5
A solid sphere and a hollow sphere of the same mass and radius are rotating with the same angular velocity about their respective diameters. If $E_S$ and $E_H$ are their rotational kinetic energies respectively, which of the following relationships is true? (Moment of inertia of a solid sphere is $\frac{2}{5}MR^2$ and a hollow sphere is $\frac{2}{3}MR^2$ )
$E_S = E_H$
$E_S = \frac{3}{5} E_H$
$E_S = \frac{5}{3} E_H$
$E_S = \frac{2}{5} E_H$
$E_S = \frac{2}{3} E_H$
Q6
Two point masses $2m$ and $3m$ are placed on the $x$ -axis at $x = 0$ and $x = 10\,\text{cm}$ respectively. The centre of gravity of the system is at:
$x = 2\,\text{cm}$
$x = 4\,\text{cm}$
$x = 5\,\text{cm}$
$x = 6\,\text{cm}$
$x = 8\,\text{cm}$
Q7
For a bipolar junction transistor operating in the active region, which of the following equations correctly relates the emitter current ( $I_E$ ), base current ( $I_B$ ), and collector current ( $I_C$ )?
$I_C = I_E + I_B$
$I_B = I_E + I_C$
$I_E = I_C - I_B$
$I_E = I_B + I_C$
$I_C = I_E \times I_B$
Q8
What is the primary function of a moderator in a nuclear fission reactor?
To absorb excess neutrons and stop the chain reaction.
To slow down fast neutrons to increase the probability of fission.
To transfer heat from the reactor core to the steam generator.
To provide the initial neutrons required to start the reactor.
To absorb alpha and beta particles emitted during fission.
Q9
A long metal rod is heated at one end to a constant temperature $T_1$ , while the other end is kept at a lower constant temperature $T_2$ . The ambient temperature is $T_0$ ( $T_0 < T_2$ ). Which of the following statements is incorrect regarding the steady state?
If the rod is perfectly lagged, the temperature gradient along the rod is constant.
If the rod is unlagged, the rate of heat flow along the rod decreases towards the cooler end.
If the rod is unlagged, the magnitude of the temperature gradient decreases towards the cooler end.
The total heat supplied to the unlagged rod at the hot end is equal to the heat extracted at the cold end.
For the unlagged rod, the temperature at the midpoint is less than $\frac{T_1 + T_2}{2}$ .
Q10
Which of the following statements correctly describes the condition for a body to float in equilibrium on the surface of a liquid?
The weight of the body is greater than the upthrust.
The density of the body is greater than the density of the liquid.
The weight of the liquid displaced by the immersed part equals the total weight of the body.
The volume of liquid displaced equals the total volume of the body.
The upthrust acts through the centre of gravity of the body.