1. Consider the circuits below that are located side by side as shown. One of these circuits includes a thermistor, which decreases in resistance as it increases in temperature.

If the switch in the circuit on the left is closed, what will happen to the brightness of the lamp over time, and why?

2. The albedo at the poles of Earth during a particular day is 0.8. What is the value of the absorbed intensity if the solar intensity is 700 W m^−2?

3. An electric circuit is connected as shown. An electric current of $2A$ flows through the electric cell with an internal resistance $r$.

What is the value for $r$ ?

4. Two solid substances of equal mass are heated with the same power input. The graph below shows how the temperatures of the substances vary with time during heating.

Which of the following statements are correct?

• I.	Substance $A$ has a lower specific heat capacity than Substance $B$ when they are in the same physical state.
  II.	The specific heat capacity of each substance is lower in the solid state than the liquid state.
  III.	Substance $A$ has a lower specific latent heat of fusion than Substance $B$.

5. The following graph shows the relationship between current and potential difference across an unknown component in a series circuit.

Which of the following is true about the component?

6. Solar radiation is incident on a planet, whose surface absorbs 65% of incident intensity. What is the albedo of the planet?

7. Gas System A contains non-interacting molecules of negligible size at pressure P, whilst Gas Systems B and C contain large, strongly interacting molecules at pressures $10P$ and P/2, respectively.

Which line of the table correctly describes how closely the three systems resemble an ideal gas?

8. A light dependent resistor (LDR) and a $10k\Omega$ resistor are connected in series to a $12V$ D.C supply as shown

When the LDR is in the dark it has a resistance of $20k\Omega$ . Which of the following gives the potential difference $V$ across the light dependent resistor under these conditions?

9. An area on the Earth's surface receives an average solar intensity of 250 Wm^−2. What is the minimum area of photovoltaic cells needed to generate 2 kW of electrical power if the photocells operate at 40% efficiency?

10. The average radius of Neptune's orbit around the Sun is approximately 30 times the orbital radius of earth. Estimate the solar constant of Neptune.

11. If the current in the circuit below is 0.5 A, what is the potential difference $V$?

12. A cell is connected to a variable resistor. The terminal potential difference (p.d.) and current through the cell are measured and plotted on the graph shown. What is the internal resistance of the cell?

13. A cylinder of fixed volume contains $n$ moles of an ideal gas at constant temperature. An additional $n$ moles of the same gas is forced into the cylinder via a one-way valve without changing the temperature. Which of the following best explains the final pressure in the cylinder?

14. If the radius of a segment of wire is doubled, and its length decreases by half, by what factor does the wire's resistance change?

15. The diagram below shows a circuit connected to a 12$V$ battery with negligible internal resistance.

What is the value of the current $I$ through the $2\Omega$ resistor?

16. Under what conditions of density and pressure does the following graph represent how the volume of a real gas varies with temperature at constant pressure?

17. A chemical reaction occurs inside a solid of mass $m$ and specific heat capacity $c$. The initial temperature of the solid is $50K$.

What is the minimum energy that the reaction must release to increase the temperature of the solid to 100$°C$?

18. Which of the following average properties of the molecules inside piston containing an ideal gas piston stay constant when the piston expands at constant temperature?

• I.  Intermolecular potential energy.
• II.  Kinetic energy.
• III.  Frequency of collisions.

19. An electron accelerates through a potential difference of $7kV$. How much work is done on the electron by the field?

20. A spherical object of surface area $A$ and absolute temperature $T$ can be regarded as a black body. The power of the radiation emitted from the object is $P$. What would be the power of the radiation emitted by an object with an absolute temperature of $2T$ and a surface area of A/2?

21. A body of water loses energy at a constant rate. Assume that the specific heat capacity of ice is half the specific heat capacity of liquid water.

Which graph shows a possible variation of temperature with time?

A.			B.
C.			D.

22. Which of the following real gases at atmospheric pressure would be least likely to approximate to an ideal gas?

23. An ideal gas is held in a container of volume $V$ and at pressure $P$. Gas is pumped into the container so that the number of molecules doubles and heat is added so that the average kinetic energy of the gas also doubles. The volume is adjusted so that the pressure remains constant. What is the new volume of the container?

24. Container 1 contains 128g of oxygen (32g mol^−1) and Container 2 contains 56 g of nitrogen (28gmol^−1). The graph shows how the pressure $P$ inside each container varies with volume V at constant temperature ($R$ is the molar gas constant).

Which line of the table gives the temperature inside the two containers?

25. A light bulb is lit by $1kJ$ of energy being transferred to the bulb by a potential difference of $200V$. This transfer happens over a time of 2 seconds.

What is the current passing through the bulb?