CSEC Physics Paper 2 May/June 2018 - Free CXC Past Paper with Answers

An atom consists of three types of particles: protons, neutrons and electrons.

Complete the following table to show the charge of EACH particle.

TABLE 2. CHARGE OF PARTICLES IN AN ATOM

For the element $^{226}_{88}\text{Ra}$, determine the number of EACH of the three particles referred to in (a) (i).

Protons

Neutrons

Electrons

State ONE similarity and ONE difference between the isotopes of an element.

Similarity

Difference

Define the term 'half-life' of a radioactive substance.

The element thorium (Th) has a half-life of 24 days and undergoes beta-decay. Calculate the time it would take for 10 grams of thorium to decay to 1.25 grams.

Define the term 'electric field'.

Draw the electric field formed between the parallel plates shown in Figure 3.

Figure 3. Parallel plates

A lightning strike is an example of an electrostatic hazard.

A lightning strike is an example of an electrostatic hazard.

State ONE other hazard of static charge.

State ONE useful application of static charge.

The graph in Figure 4 shows the alternating voltage output from a generator.

Figure 4. Alternating voltage output from a generator

Using the graph in Figure 4, determine the (i) value of the peak to peak voltage (ii) period of the alternating voltage, in seconds (iii) frequency of the alternating voltage from the supply.

value of the peak to peak voltage

period of the alternating voltage, in seconds

frequency of the alternating voltage from the supply.

Define each of the following terms.

Specific heat capacity

Heat capacity

Write the formula to show the relationship between the specific heat capacity, $c$, and heat capacity, $C$, of a body.

Some students were asked to carry out an experiment to determine the specific heat capacity of a metal. They used the apparatus shown in Figure 5.

Figure 5. Apparatus to determine the specific heat capacity of a metal

The switch was closed for a time interval of 900 s and the following readings were obtained.

• Mass of metal block = 5 kg
• Change in temperature = 50 °C
• Ammeter reading = 8.5 A
• Voltmeter reading = 12 V

Using the data on page 14, calculate the specific heat capacity of the metal, stating any assumption(s) made.

State Hooke's law.

State Hooke's law.

With the aid of a labelled, sketched graph, explain what is meant by 'elastic limit'.

A steel spring has a spring constant of $2 \times 10^2 \text{ N m}^{-1}$.

Calculate the weight of an object which when attached to the unloaded spring produces an extension of 50 mm. The elastic limit is NOT exceeded.

$\text{Spring Constant} = \frac{\text{Force}}{\text{Extension}}$

The object attached to the spring in (b) fell from rest and hit the ground after two seconds. Calculate the velocity of the object on hitting the ground.

$[g = 10 \text{ m s}^{-2}]$

The transformer is a commonplace technological tool used in our daily lives. Figure 6 shows one type of transformer used in electricity distribution.

State the name of the parts labelled A, B, C and D in Figure 6.

Identify the type of transformer shown in Figure 6.

State the formula that relates voltage, $V$, to number of turns, $n$, in a transformer.

A transformer has 5000 turns in its secondary coil and 50 turns in its primary coil. The voltage supplied to its primary coil is 12.0 V a.c. and a current of 6.0 A flows in its primary coil.

Calculate

the input power of the transformer

the voltage across the secondary coil

the maximum secondary current if the transformer is 100% efficient.