Physics
PART B
40 Marks
TRIAL C FINAL
PART B Question and Answer Booklet
Question 1 [6 Marks]
A ray of monochromatic yellow light travelling in glass strikes a glass/air boundary at the critical angle as shown in the diagram.
1.1 For this particular yellow light the refractive indexof this glass is 1.54
Complete the diagram to show the path (or paths) followed by the yellow light immediately after striking the boundary.
1.2 Calculate the angle ic .
1.3 Complete the diagram below to show the path (or paths) that would be followed by red
light incident at the critical angle for yellow.
The refractive index for red is less than for yellow.
Question 2 [6 Marks] The graph shows a transverse harmonic wave that is travelling to the right at 20.0 m s-1.
2.1 Calculate the period of this wave.
2.2 Calculate the displacement of particle P from its equilibrium position.
2.3 Taking the instant shown as time t = 0 s, sketch a displacement - time graph for particle P over the next cycle.
Question 3 [6 Marks]
A vibrating tuning fork is held at the open end of a long tube that is closed at the other end by a piston. Sliding the piston back and forth can vary the length, l.
When the piston is moved along the tube, starting from l = 0 mm, it is found that the first
resonance occurs when l = 265 mm and the second when l = 803 mm. The speed of sound in air at the temperature of the experiment is known to be 344 m s-1.
3.1 Calculate the wavelength of the sound wave emitted by the tuning fork.
3.2 Calculate the frequency of the tuning fork.
3.3 For what value of l would you expect the third resonance to occur?
Question 4 [6 Marks]
A proton enters a uniform. magnetic field at M and emerges at Q as shown in the diagram.
4.1 Calculate the magnitude of the magnetic force on the proton as it enters the field. The speed of the proton is 3.5 × 104 m s-1.
4.2 Calculate the distance between M and Q.
4.3 Show that if the area of the field is large enough so that the proton cannot escape from the other side or the edges, the time the proton spends in the field does not depend on its speed and calculate this time.
Question 5 [6 Marks]
In the diagram XY is a ray of plane polarised electromagnetic radiation that is travelling to the east in air. The frequency ofthis radiation is 150 MHz.
At a certain instant at point A the electric field has its maximum value and is directed vertically upwards.
5.1 What is the direction of the magnetic field at A at this same instant?
5.2 What is the direction of the electric field at B at this same instant?
5.3 What is the direction of the magnetic field at B 30.0 ns after this instant?
Question 6 [10 Marks]
A thick walled cylindrical pipe of inner radius 0.090 m and outer radius 0.110 m has a mass of 8.50 kg. This pipe rolls from rest without slipping, sliding or bouncing 0.75 m down a plane inclined at 25o to the horizontal.
6.1 Calculate the gravitational potential energy lost by the system when the pipe rolls 0.75m down the plane.
6.2 Obtain an expression for the total kinetic energy of the rolling pipe with the speed of the centre of mass as the only unknown.
6.3 Calculate the speed of the centre of mass of the pipe when the pipe has rolled 0.75 m down the plane.
6.4 Calculate the linear acceleration of the centre of mass of the pipe down the plane.
6.5 Calculate the force of friction that the plane exerts on the rolling pipe.