Question

4 Fig. 9.1 shows two separate coils of wire wound around an iron core. Fig. 9.1 An a.c. supply is connected across the primary coil and a 12 V lamp is connected across the secondary coil. The lamp glows with normal brightness. (a) State the name of the device shown in Fig. 9.1. [1] (b) Explain why there is a current in the lamp. \( \qquad \) \( \qquad \) \( \qquad \) \( \qquad \) \( \qquad \) [4] (c) (i) The coil connected to the lamp has 450 turns. The e.m.f. of the a.c. supply is 240 V . Calculate the number of turns on the coil connected to the a.c. supply. number of turns = \( \qquad \) [2] (ii) A 240 V d.c. supply is used instead of the 240 V a.c. supply. Tick one box to indicate what happens to the lamp. \( \square \) glows more brightly \( \square \) glows with the same brightness \( \square \) glows less brightly [1] \( \square \) does not glow [Total: 8]

          4 Fig. 9.1 shows two separate coils of wire wound around an iron core.

Fig. 9.1
An a.c. supply is connected across the primary coil and a 12 V lamp is connected across the secondary coil. The lamp glows with normal brightness.
(a) State the name of the device shown in Fig. 9.1.
[1]
(b) Explain why there is a current in the lamp.
\( \qquad \)
\( \qquad \)
\( \qquad \)
\( \qquad \)
\( \qquad \)
[4]
(c) (i) The coil connected to the lamp has 450 turns. The e.m.f. of the a.c. supply is 240 V .

Calculate the number of turns on the coil connected to the a.c. supply.
number of turns = \( \qquad \)
[2]
(ii) A 240 V d.c. supply is used instead of the 240 V a.c. supply. Tick one box to indicate what happens to the lamp.
\( \square \) glows more brightly
\( \square \) glows with the same brightness
\( \square \) glows less brightly
[1]
\( \square \) does not glow
[Total: 8]

4 Fig. 9.1 shows two separate coils of wire wound around an iron core.

Fig. 9.1
An a.c. supply is connected across the primary coil and a 12 V lamp is connected across the secondary coil. The lamp glows with normal brightness.
(a) State the name of the device shown in Fig. 9.1.
[1]
(b) Explain why there is a current in the lamp.

[4]
(c) (i) The coil connected to the lamp has 450 turns. The e.m.f. of the a.c. supply is 240 V .

Calculate the number of turns on the coil connected to the a.c. supply.
number of turns =
[2]
(ii) A 240 V d.c. supply is used instead of the 240 V a.c. supply. Tick one box to indicate what happens to the lamp.
□ glows more brightly
□ glows with the same brightness
□ glows less brightly
[1]
□ does not glow
[Total: 8]

Added by Darnell C.

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