David Sang and Graham Jones Solutions for Chapter: Practical Circuits, Exercise 9: EXAM-STYLE QUESTIONS

This is a potentiometer circuit.

(a) (ii) State the readings on the voltmeter when the jockey is connected to A and when it is connected to B. (You may assume that the driver cell has negligible internal resistance.)

This is a potentiometer circuit.

Draw a circuit diagram to show how the potentiometer could be used to compare the e.m.f.s of two batteries.

This is a potentiometer circuit.

When a pair of $4\Omega$ resistors are connected in series with a battery, there is a current of $0.60 \mathrm{A}$ current through the battery. When the same two resistors are connected in parallel and then connected across the battery, there is a current of $1.50 \mathrm{A}$ through it. Calculate the e.m.f. and the internal resistance of the battery.

A potentiometer, which consists of a driving cell connected to a resistance wire of length $100 \mathrm{cm}$, is used to compare the resistances of two resistors. Draw a diagram to show the circuits that are used to compare the two resistances.

A potentiometer, which consists of a driving cell connected to a resistance wire of length $100 \mathrm{cm}$, is used to compare the resistances of two resistors. When resistor $R_1$ alone is tested the length of resistance wire for balance is $15.4 \mathrm{cm}$. There is an uncertainty in measuring the beginning of the resistance wire of $0.1 \mathrm{cm}$, and in establishing the balance point of a further $0.1 \mathrm{cm}$. Determine the uncertainty in the balance length. When $R_1$ and $R_2$ are tested in series the balance length is $42.6 \mathrm{cm}$. There are similar uncertainties in measuring this balance length.

A potentiometer, which consists of a driving cell connected to a resistance wire of length $100 \mathrm{cm}$, is used to compare the resistances of two resistors. When resistor $R_1$ alone is tested the length of resistance wire for balance is $15.4 \mathrm{cm}$. There is an uncertainty in measuring the beginning of the resistance wire of $0.1 \mathrm{cm}$, and in establishing the balance point of a further $0.1 \mathrm{cm}$. Calculate the ratio of $\frac{R_1}{\left(R_1+R_2\right)}$

A potentiometer, which consists of a driving cell connected to a resistance wire of length $100 \mathrm{cm}$, is used to compare the resistances of two resistors. When resistor $R_1$ alone is tested the length of resistance wire for balance is $15.4 \mathrm{cm}$. There is an uncertainty in measuring the beginning of the resistance wire of $0.1 \mathrm{cm}$, and in establishing the balance point of a further $0.1 \mathrm{cm}$. Calculate the value of the ratio of $\frac{R_1}{R_2}$.

A potentiometer, which consists of a driving cell connected to a resistance wire of length $100 \mathrm{cm}$, is used to compare the resistances of two resistors.

(b) When resistor $R_1$ alone is tested the length of resistance wire for balance is $15.4 \mathrm{cm}$. There is an uncertainty in measuring the beginning of the resistance wire of $0.1 \mathrm{cm}$, and in establishing the balance point of a further $0.1 \mathrm{cm}$.

(iv) Calculate the uncertainty in the value of the ratio $\frac{R_1}{R_2}$.