CSEC Physics Paper 2 May/June 2021 - Free CXC Past Paper with Answers

To determine the spring constant (or stiffness) of a spring, a student placed different masses, $m$ , on a hanger that was attached to a spring and recorded the length, $l$ , of the spring. Table 1 shows the mass and corresponding values of length.

TABLE 1: MASS ADDED, $m$ , AND CORRESPONDING LENGTH VALUES, $l$ , OF A SPRING

Complete Table 1 by inserting the missing force and extension values in Columns 2 and 4 respectively.

Using the grid provided in Figure 1 on page 5, plot a graph of extension, $e$ , versus force, $F$ .

Calculate the gradient, $S$ , of the graph on page 5.

Given the gradient, $S = \frac{1}{k}$ , calculate the spring constant, $k$ .

Given that $F = ke$ , calculate the length, $l$ , when a force of $8.0 \text{ N}$ is applied. Assume that the spring obeys Hooke's law.

Define EACH of the following terms.

State the TWO conditions necessary for a body to be in equilibrium.

Figure 2 shown below is a diagram of a non-uniform wooden plank, $AB$ , which is $2.0 \text{ m}$ long and weighs $1000 \text{ N}$ . The plank is supported from a ceiling by two vertical springs, $P$ and $Q$ . The plank is attached at a distance of $0.5 \text{ m}$ from each end. $C$ is the centre of gravity as shown in Figure 2.

Figure 2. Diagram of a non-uniform wooden plank supported by two springs, $P$ and $Q$

When the plank is horizontal, the tension in Spring $P$ is $600 \text{ N}$ .

Calculate the tension in Spring $Q$ . Show ALL working.

By taking moments about $A$ , determine the horizontal distance from $P$ to $C$ .

State why the centre of gravity is located closer to the point $P$ than the point $Q$ .

Waves can be described as transverse or longitudinal.

Explain what is meant by a 'transverse wave'.

Give ONE example of a 'transverse wave'.

Define the term 'ultrasound'.

State ONE example of the application of ultrasound.

Figure 3 shows the path of a light ray from air through a cube of ice, along with two rays showing partial reflection.

Figure 3. Light ray passing through a cube of ice

Determine

the angle of incidence on the face $MN$ .

the angle of reflection on the face $MN$ .

the angle of refraction at the face $MN$ , given that the refractive index of ice is 1.31.

On the diagram in Figure 3 on page 11, label the critical angle, $\theta_c$ , for ice.

SECTION B

Answer ALL questions.

On Figure 4 below, sketch the graph of pressure versus temperature (in degrees Celsius) for an ideal gas.

Figure 4. Pressure versus temperature

Explain how the graph could be used to derive the Kelvin scale.

Using $T$ to represent the Kelvin temperature and $\theta$ to represent the Celsius temperature, state the mathematical relationship between the Kelvin and Celsius temperature scales.

A container stores $5.0 \text{ m}^3$ of gas at a pressure of 13 atmospheres and a temperature of $-23 \text{ }^\circ\text{C}$ . Calculate the volume that the same gas would occupy at a temperature of $27 \text{ }^\circ\text{C}$ and atmospheric pressure of 1 atmosphere.

Blocks X and Y in Figure 5 are identical except for their temperatures.

Figure 5. Diagram of two identical blocks with different temperatures

Explain the difference in the motion of the particles in Block X compared with the motion of the particles in Block Y.

In which direction would thermal energy be transferred?

State the condition under which the transfer of thermal energy would cease.

Figure 6 shows a simple d.c. motor which consists of a coil of wire, $ABCD$ , between the poles of a magnet. The dotted line represents an axle about which the coil can turn. A current flows through the coil in the direction shown by the arrows.

Figure 6. Simple d.c. motor

Draw the magnetic field between the poles of the magnet on Figure 6.

State the direction in which side $DA$ of the coil will move as the current starts flowing through the circuit.

Name the rule used to determine the direction in which side $DA$ of the coil moves.

Explain why a split-ring (commutator) is used in a d.c. motor.

Figure 7 shows a graph of the variation of voltage with time across the output terminals of an a.c. generator.

Figure 7. Graph of voltage against time

Calculate the value of the frequency for the generator.

The peak voltage is applied by the generator across a $100.0 \ \Omega$ resistor. Calculate the peak value of the current in the resistor.

The generator is subsequently rotated at twice the frequency in (b) (i). State the effect this will have on

the period of the output

the value of the output voltage.

Radium-226 is radioactive and is represented by the nuclide $^{226}_{88}\text{Ra}$ .

For a neutral atom of Radium-226, state

the number of protons

the number of neutrons

the number of electrons.

A Radium-226 nucleus decays by $\alpha$ -particle emission to Radon (Rn) nucleus.

Explain what is meant by the term 'radioactivity'.

Complete the equation for the decay of Radium-226. $^{226}_{88}\text{Ra} \rightarrow$

Radium-226 has a half-life of 1600 years.

Define the term 'half-life'.

At a certain time, a sample contains $8.0 \times 10^8$ Radium nuclei. Calculate the number of $\alpha$ -particles emitted by the Radium nuclei in the next 4800 years.

How much more time will elapse before the number of Radium nuclei remaining falls to $0.5 \times 10^8$ ?

CSEC Physics Paper 2 May/June 2021 Questions

Question 1 (25 marks)

TABLE 1: MASS ADDED, $m$ , AND CORRESPONDING LENGTH VALUES, $l$ , OF A SPRING

Question 2 (15 marks)

Figure 2. Diagram of a non-uniform wooden plank supported by two springs, $P$ and $Q$

Question 3 (15 marks)

Figure 3. Light ray passing through a cube of ice