# Mock 2010

Do ALL questions

Q1

A 2kg object moving with a velocity of 8m/s collides with a 4kg object moving at a velocity of 5 m/s along the same line.

If the 2 objects join on impact calculate their common velocity when they

1. in opposite directions
2. travelling in the same direction

(12)

Describe the apparatus that might have been used to carry out this experiment

(9)

What might have held the two objects together

(6)

What readings needed to be taken in order to calculate the velocity

(6)

Why does this experiment need to be carried out in a closed system

(7)

Q2

A student passed a ray of light through a rectangular glass block from air. He measured the angles of incidence for five rays of light entering the glass block and the cooresponding angles of refraction the following results were obtained

Draw a suitable graph and explain how this verifies snells law

(15)

From the graph determine the refractive index of the glass

(9)

Which value of r would be least accurate? Explain

(6)

Describe another experiment to determine the refractive index of the glass block

Include formula used

(10)

Q3

In an experiment to investigate the variation of the fundemental frequency of a string with length L the following results were found

How would the student have known the string was vibrating at its fundamental frequency

(6)

Draw a suitable graph to illustrate the relationship between the fundemental frequency the length of the streched string. State this relationship

(15)

Determine from the graph the ratio of the Tension to the mass per unit length.

(12)

Explain how the temperature would affect this value

(6)

Q4

The electrical resistance per metre of nichrome wire was measured at different diameters. The results are in the table

Name the apparatus used to find the diameter of the wire. Why is it advisable to measure the diameter of any wire more than once?

(6)

Assuming each piece of wire has a circular cross section, calculate the cross sectional area of each wire.

(9)

Draw a suitable graph to illustrate the relationship between R & A

(15)

Use your graph to estimate the resistivity of the nichrome alloy

(10)

Q5

1. When would an object moving at constant speed have an acceleration
2. If the Potential energy of a body is 980J at a height of 2m, what is the weight of the body
3. The critical angle for water is 48.6o . Find its refractive index.
4. A diffraction grating has 500 lines per mm. What is the distance in meters between adjacent lines.
5. Give a use of capacitors
6. State Lenz' law
7. Who discovered radioactivity in 1890
8. What initiates the fission of a Uranium nucleus
9. Name 2 factors on which the back emf of a motor depend
10. Distinguish between baryons and leptons.

Q6

Distinguish between a scalar quantity and a vector quantity

(6)

Describe an experiment to find the resultant of two vectors.

(18)

Define acceleration

(6)

A body is travelling with a velocity u in a certain direction. It then uniformly accelerates, a, in the same direction for a time t. Derive a expression for its displacement after time t in terms of u and a

(11)

A car accelerates from rest to a speed of 15m/s in a time of 4 seconds. it then moves at this speed for the next 6 s

Calculate

1. The total distance travelled by the car.
2. The average speed of the car

(15)

Q7

Explain the term Resonance. Give an example

(9)

A tuning fork is set vibrating over a resonance tube which can be varied from 0cm to 110cm in lenght. At what lenghts would you expect to find resonance if the tuning fork has a frequency of 425Hz and the speed of sound in air is 340m/s

(12)

In the Laboratory, the vibrating tuning fork is held slightly above the resonance tube. How is this error in the measurement overcome?

(6)

A police car siren emits a continous note of frequency 1kHz as it passes a stationary observer at traffic lights if the police car is travelling at 30m/s towards the observer the frequency of the note appears higher. Explain using a diagram why the note appears to be higher. Name this phenomena.

(14)

If the velocity of sound is 336 m/s on this particular day what is the frequency heard by the observer when the car is

1. approaching the observer
2. moving away from the observer

Give another application of this phenonmen.

(15)

Q8

(6)

Radon-222 is an alpha emitter. Write an equation to show the decay of radon-222.

(6)

Why is radon considered to be a health hazard

(5)

In an experiment to determine the half-life of a short lived radioactive isotope a measure of the activity A for a sample of the isotope was obtained at various times t, the following results were recorded

Draw a suitable graph on graph paper to illustrate the change in activity with time, and from this graph determine the half-life of the isotope

(21)

Describe the apparatus that might have been used in this experiment. What reading should be recorded before the radioactive isotope is introduced

(12)

Give 2 safety precautions which should be observed when handling radioactive isotopes

(6)

If the velocity of sound is 336 m/s on this particular day what is the frequency heard by the observer when the car is

1. approaching the observer
2. moving away from the observer

Give another application of this phenonmen.

(15)

Q9

Define Resistance & Capacitance

(12)

Two resistors are connected in parallel in a circuit. Show that the effective resistance of the circuit is (9)

Outline an experiment to show that a capacitor stores energy

(12)

The diagram below shows a capacitor connected in series to a power supply and a bulb

(i) explain why the bulb does not light

(6)

(ii) Suggest a change to the circuit that would light the bulb, explain your choice

(8)

(iii) What is the charge on the the plates when the energy stored is 0.52mJ

(9)