1. 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?

2. A student constructed the series circuit below.

After closing the switch, which of the following is true about how the temperature of component A and current in the circuit will change with time?

3. 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?

4. An ideal gas piston of total volume 900 cm^3 contains 600 cm^3 of air and 300 cm^3 of water at a temperature of 27°C. The system is cooled and the piston contracts at constant pressure.

What is the approximate total piston volume at the point where the water first starts to freeze?

5. 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 $B$.

6. Water in a beaker is heated on a hot plate at a rate $P$. The graph shows the change in temperature of the water over time.

Which graph correctly shows the new change in temperature of the water when the rate of thermal energy transfer is increased?

The original graph is shown by the dotted line.

A.			B.
C.			D.

7. The following three statements give possible reasons why the average intensity of sunlight incident on a solar panel during a day on earth is only a fraction of the solar constant.

• I.	Scattering of sunlight in the atmosphere
  II.	Rotation of the earth
  III.	The surface of the solar panel is not perpendicular to incident of sunlight

Which of the statements are correct?

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

9. 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 $r$ ?

10. The variation of terminal potential difference $V$ across an electric cell with current $I$ coming out of the cell is shown in the graph.

What are the values of the emf $ϵ$ and internal resistance $r$ of the electric cell used in this circuit?

11. 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?

12. 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.

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

14. 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?

15. A material with a mass of m is heated. The graph shows the variation of the temperature of the material with the energy supplied.

Which one of the following gives the specific heat capacity of the material?

16. 100 ml of water at 20oC is poured in an aluminum container and heated at a constant rate until all of the water is boiled. After time t1​ water starts to boil, and at time t2​ all of the water has boiled away.

Which of the following statements are correct?

• I.	If a glass container with the same mass is used instead of aluminum, t1​ increases. (cglass​)
  II.	If the container with water is thermally isolated, t2​ decreases.
  III.	If more water is added to the container, t1​ increases.

17. An immersion heater of constant power output is used to supply thermal energy to a cup of water at 373 $K$. The heater is turned on at time $t=0$. Which graph shows a possible variation of temperature $T$ of the water, with time t?

A.			B.
C.			D.

18. An ideal gas is enclosed in a syringe. The gas has a volume of 20 mL, a temperature of 20oC, and pressure of $10kPa$. The syringe is heated to 40oC, and the volume of the gas is reduced to 5 mL.

What is the new pressure?

19. A quantity of 2000 $kg$ Carbon Dioxide (CO2​) is maintained in a container tank. The molar mass of Carbon Dioxide (CO2​) is 44 g mol^−1. Determine the correct estimate of the number of Carbon Dioxide (CO2​) molecules in the container tank.

20. 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$°C$?

21. An ideal gas is enclosed in a container of fixed volume. When the temperature of the gas is 27oC, its pressure is $p$. Calculate the pressure in the gas when it is heated to 54oC.

22. An ideal gas is in a fixed volume container which sits on an electronic balance. More of the same gas is added to the container. Which of the following will not change?

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

24. 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?

25. 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?