Which of the following best describes the primary function of a chemical cell?

A. Convert mechanical energy to electrical energy

B. Convert electrical energy to mechanical energy

C. Convert chemical energy to electrical energy

D. Convert electrical energy to chemical energy

The EMF of a cell is 1.5V, but when connected to a circuit, its terminal voltage drops to 1.2V. What is the most likely cause of this drop?

A. External resistance is too high

B. The cell is fully charged

C. Internal resistance of the cell

D. The cell is not connected properly

Two identical cells, each of EMF 1.5V and negligible internal resistance, are connected in series. What is the total potential difference across the combination?

A. 0.75V

B. 1.5V

C. 3.0V

D. 6.0V

Which of the following best describes the electrode reaction in a chemical cell?

A. Physical change at the electrode

B. Mechanical movement at the electrode

C. Chemical reaction at the electrode

D. Electrical discharge at the electrode

Why is the terminal voltage of a cell usually less than its EMF when supplying current to an external circuit?

A. Due to the chemical reactions in the cell

B. Because of the magnetic field around the cell

C. Due to the internal resistance of the cell

D. Because of the external resistance of the circuit

a) Describe the fundamental chemistry behind a chemical cell and explain how energy conversion takes place within it. [3]

b) A chemical cell has an electrode potential of 1.5 V. If a current of 2 A flows through it for 10 seconds, calculate the amount of charge that has passed through the cell. [2]

a) Differentiate between electromotive force (EMF) and terminal voltage of a cell. [3]

b) A battery with an EMF of 9 V and an internal resistance of 1 ohm is connected to an external resistor of 8 ohms. Calculate the terminal voltage of the battery. [2]

a) Explain the significance of combining cells in series and parallel. [3]

b) Two identical cells, each with an EMF of 1.5 V and negligible internal resistance, are connected in parallel. What is the resultant EMF of the combination? [2]

a) Describe the role of electrode reactions in the functioning of a chemical cell. [3]

b) If a chemical cell has an internal resistance of 0.5 ohms and is connected to an external load of 4.5 ohms, calculate the total resistance of the circuit. [2]

c) Given that the EMF of the cell is 3 V, determine the current flowing through the circuit. [2]

a) Explain the difference between resistivity and conductivity and their significance in the context of electrical circuits. [3]

b) A material has a resistivity of 1.7 x 10^-8 ohm.m. Calculate its conductivity. [2]

c) How does temperature generally affect the resistivity of metals? [2]

What is the main advantage of connecting cells in parallel?

A. Increases the total EMF

B. Increases the total internal resistance

C. Provides greater current capacity

D. Reduces the energy of the cells

In a certain chemical cell, the anode undergoes oxidation. What happens at the cathode?

A. Oxidation

B. Reduction

C. No reaction

D. Physical change

Which of the following factors does NOT affect the resistivity of a material?

A. Temperature

B. Length of the material

C. Type of material

D. Cross-sectional area of the material

A battery is made by connecting three cells of EMF 2V each in series. If one of the cells is reversed, what will be the net EMF of the battery?

A. 6V

B. 2V

C. 4V

D. 0V

Which of the following is NOT a real-world implication of power in circuits?

A. Determining the efficiency of electrical appliances

B. Calculating the cost of electricity

C. Predicting the chemical reactions in a cell

D. Designing safe electrical systems

a) Define EMF and terminal voltage in the context of a chemical cell. [3]

b) A battery has an EMF of 6 V and an internal resistance of 2 ohms. If the current drawn from the battery is 1 A, calculate the terminal voltage. [2]

c) How does the terminal voltage change if the current drawn is increased to 2 A? [2]

a) Describe how cells can be combined in series and parallel and the implications of each arrangement. [3]

b) Two cells, each of 1.5 V, are connected in series. What is the total EMF? [2]

c) If these cells are instead connected in parallel, how does the total EMF change? [2]

a) Describe the primary chemical reactions that occur in a zinc-carbon cell. [3]

b) If a zinc-carbon cell has an EMF of 1.5 V and is supplying a current of 0.5 A to a circuit, calculate the energy supplied by the cell in 10 minutes. [3]

c) How does the internal resistance of a cell affect its terminal voltage? [2]

d) A zinc-carbon cell has an internal resistance of 0.1 ohms. If it is supplying a current of 0.5 A, calculate the voltage drop across the internal resistance. [2]

a) Explain the difference between primary and secondary cells. [3]

b) A secondary cell has a capacity of 2000 mAh. If a device draws a current of 500 mA from this cell, how long will the cell last before it needs recharging? [3]

c) Define the term 'deep discharge' in the context of secondary cells. [2]

d) Why is deep discharge harmful for most secondary cells? [2]

a) Describe the principle behind the functioning of a lead-acid battery. [3]

b) A lead-acid battery used in a car has an EMF of 12 V. If the headlights and radio together draw a current of 10 A, calculate the power consumed. [3]

c) How does the efficiency of a battery change with temperature? [2]

d) Why is it recommended to avoid completely discharging a lead-acid battery? [2]