Unit 2 Physics June 2010

Please choose one of the following options for each question:

1. A formula for the speed v of ocean waves, in terms of the acceleration of free fall g and the wavelength λ, is v = √(gλ).
Which of the following is the correct expression for the SI base units on the right hand side of this formula?

2. Which line of the table correctly summarises the changes in wave characteristics when moving from ultraviolet to infrared in the visible spectrum?

3. The diagrams show connected wires that carry currents I1, I2, I3 and I4.
The currents are related by the equation I1 + I2 = I3 + I4
Identify the diagram that this equation applies to.

4. A 100 W lamp connected to the 230 V mains is replaced by a lamp which has twice the resistance. The power of the new lamp is

5. The diagram shows some of the electron energy levels for the hydrogen atom with four possible transitions.

The transition that would result in the emission of the longest wavelength is

6. Ultrasound pulses are used to detect shoals of fish in the sea. A shoal of fish is at a depth of 300 m and the speed of ultrasound in water is 1500 m s–1. The time interval between transmitting and receiving the pulse will be

7. The graph shows the displacement of molecules against their distance from a wave source. Which of the points A to D, marked on the graph, has a phase difference of 270° with point X?

8. The behaviour of light can be described in terms of waves or particles. The particle nature of light can be demonstrated by

9. The current in a wire

10. The graph shows the relationship between potential difference V and current I for a fixed 20 Ω resistor and a filament lamp.

The resistor and lamp are placed in series with a 9 V battery of negligible internal resistance. The current in the circuit is