IGCSE Physics Paper-1: Specimen Questions with Answers 99 - 100 of 109
Question number: 99
Question
The circuit shown contains four lamps and three switches.
Circuit Diagram Consist of Three Switches and Four Lamps.
Figure shows the circuit diagram consists of four lamps and three switches.
Which switches must be closed to light only lamps 1 and 3?
Choices
| Choice (4) | Response | |
|---|---|---|
| a. | switch S2 and switch S3 only |
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| b. | switch S1 and switch S3 only |
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| c. | switch S1 only |
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| d. | switch S1 and switch S2 only |
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Answer
c.Explanation
For light only lamp 1 and 3 switch S1 must be closed. As figure shows only switch S1 is must be close for completing the circuit for lamp 1 and lamp 3.
Question number: 100
Question
A straight wire carrying a current produces a magnetic field. Which diagram shows the correct shape of the field?
Choices
| Choice (4) | Response | |
|---|---|---|
| a. |  A Current Carrying Wire Passing through Plane. (Choice A) Figure a show a current carrying wire passing through a plane and it produced magnetic field on the plane. |
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| b. |  A Current Carrying Wire Passing through Plane. (Choice B) Figure a show a current carrying wire passing through a plane and it produced magnetic field on the plane. |
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| c. |  A Current Carrying Wire Passing through Plane. (Choice C) Figure a show a current carrying wire passing through a plane and it produced magnetic field on the plane. |
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| d. |  A Current Carrying Wire Passing through Plane. (Choice D) Figure a show a current carrying wire passing through a plane and it produced magnetic field on the plane. |
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Answer
d.Explanation
Magnetic field lines due to straight wire carrying current is always circular and the direction of the magnetic field line is given by right hand rules which is explained as follow,
Right Hand Rules for Current Carrying Wire and Magnetic Field
Figure shows the right hand rules for direction of the magnetic field produced by a current carrying wire.
The direction of the magnetic field is perpendicular to the wire and is in the direction the fingers of your right hand would curl if you wrapped them around the wire with your thumb in the direction of the current.