Question 5
5
The angular deflection of the needle of an ammeter varies with the current passing through the ammeter as shown in the graph. Which diagram could represent the appearance of the scale on this meter?
Answer
A
Question bank
A-Level CAIE Physics 9 1 Electric Current Question Bank
Practice A-Level CAIE Physics 9 1 Electric Current questions by syllabus topic with past-paper context, marks, difficulty and question previews on Eduninja.
Question 3
3
A jet of water hits a vertical wall at right angles, as shown in Fig. 3.1. The water hits the vertical wall with a velocity of \(5.0 \mathrm{~ms}^{-1}\) in a horizontal direction. The cross-sectional area of the jet is \(1.5 \times 10^{-4} \mathrm{~m}^{2}\). The density of the water is \(1.0 \times 10^{3} \mathrm{~kg} \mathrm{~m}^{-3}\). The water runs down the wall after hitting it.
Question 3(a)
3(a)
Show that, over a time of 1.6 s , the mass of water hitting the wall is 1.2 kg .
Answer
\((m=) \rho V\) C1 \(=1.0 \times 10^{3} \times 1.5 \times 10^{-4} \times 5.0 \times 1.6=1.2(\mathrm{~kg})\) A1
Question 3
3
Lightning occurs when charge builds up in the atmosphere, creating a potential difference between the ground and the atmosphere. During a lightning strike there is an average current of \(3.3 \times 10^{4} \mathrm{~A}\) for a time of \(2.6 \times 10^{-5} \mathrm{~s}\).
Question 3(a)
3(a)
Calculate the charge transferred during the lightning strike. charge = C
Answer
Q=I t C1 \[ \begin{aligned} =3.3 \times 10^{4} \times 2.6 \times 10^{-5} =0.86 \mathrm{C} \end{aligned} \] A1
Question 4
4
An electron in a metal rod moves randomly about a mean position. When an alternating voltage is applied to the ends of the rod, the mean position can be considered to oscillate with simple harmonic motion along the axis of the rod. Fig. 4.1 shows the variation with time t of the displacement x of the mean position from a fixed point on the axis of the rod.
Question 4(b)
4(b)
The rod has a cross-sectional area of \(4.3 \mathrm{~cm}^{2}\) and contains a number density of conduction electrons (charge carriers) of \(8.5 \times 10^{28} \mathrm{~m}^{-3}\). All of the conduction electrons in the rod may be assumed to be oscillating in phase with, and with the same amplitude as, the oscillation shown in Fig. 4.1.
Question 4(b)(i)
4(b)(i)
Use the information in (a)(iii) to calculate the magnitude \(I_{0}\) of the maximum current in the rod.
Answer
\[ \begin{aligned} I_{0} =n A v_{0} e =8.5 \times 10^{28} \times 4.3 \times 10^{-4} \times 1.1 \times 10^{-7} \times 1.60 \times 10^{-19} \end{aligned} \] C1 \(=0.64 \mathrm{~A}\) A1
Question 6
6
An electric heater is to be made from nichrome wire. Nichrome has a resistivity of \(1.0 \times 10^{-6} \Omega \mathrm{~m}\) at the operating temperature of the heater. The heater is to have a power dissipation of 60 W when the potential difference across its terminals is 12 V .
Question 6(a)
6(a)
For the heater operating at its designed power,
Question 6(a)(i)
6(a)(i)
calculate the current, current = A
Answer
\(60=12 \times I\) I=5 .(0) A A1
Question 5
5
A student sets up a circuit with a battery, an ammeter, a heater and a light-dependent resistor (LDR) all in series. The battery has negligible internal resistance. A voltmeter is connected across (in parallel with) the heater.
Question 5(b)
5(b)
The heater is a wire made of metal of resistivity \(1.1 \times 10^{-6} \Omega \mathrm{~m}\). The wire has length 2.0 m and cross-sectional area \(3.8 \times 10^{-7} \mathrm{~m}^{2}\). The reading on the voltmeter is 4.8 V . Calculate:
Question 5(b)(ii)
5(b)(ii)
the reading on the ammeter. reading on ammeter = A
Answer
\[ \begin{aligned} I =4.8 / 5.8 =0.83 \mathrm{~A} \end{aligned} \] A1
Question 29
29
For a current-carrying wire, the current can be calculated using the equation shown. What is the meaning of n ? the number of charge carriers in the wire the number of charge carriers multiplied by the volume of the wire the number of charge carriers per unit length of the wire the number of charge carriers per unit volume of the wire
Answer
D
Question 29
29
The diagram shows the symbol for a wire carrying a current I. What does this current represent? the charge flowing past a point in the wire per unit time the number of electrons flowing past a point in the wire per unit time the number of positive nuclei flowing past a point in the wire per unit time the number of protons flowing past a point in the wire per unit time
Answer
A
Question 30
30
There is an electric current in a copper wire. Which statement describing the average drift speed of the charge carriers in the wire is correct? It is nearly \(3 \times 10^{8} \mathrm{~ms}^{-1}\). It is proportional to the cross-sectional area of the wire. It is proportional to the length of the wire. It is proportional to the magnitude of the current.
Answer
D
Question 30
30
A fine mist of oil droplets is sprayed into air. As the oil droplets leave the nozzle of the spraying device they can become electrically charged. What is not a possible value for the charge on an oil droplet? zero \(1.0 \times 10^{-19} \mathrm{C}\) \(4.8 \times 10^{-19} \mathrm{C}\) \(8.0 \times 10^{-19} \mathrm{C}\)
Answer
B