Edexcel A Level Physics

Topic Questions

Resistance, Resistivity & Potential Dividers

1
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1 mark

The intensity of light incident on a light dependent resistor (LDR) can vary both its electrical resistance R and the number of charge carriers per unit volume n. The light intensity on an LDR is increased.

Which row of the table describes the effect on R and n?

  R n
A decreases decreases
B decreases increases
C increases decreases
D increases increases

 

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2
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1 mark

A light dependent resistor (LDR) and a resistor are connected to a battery, as shown.

q7-nov-2021-9ph0-01-edexcel-as-a-level-phy

The intensity of light incident on the LDR increases.
Which row of the table describes the change in the resistance of the LDR and the change in the potential difference across the resistor?

  Resistance of LDR Potential difference across the resistor
A decreases decreases
B decreases increases
C increases decreases
D increases increases

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3
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1 mark

A light dependent resistor is connected across a cell of negligible internal resistance.
The light intensity is increased.

Which of the following statements about the current is correct?

  • It decreases because there is an increase in the number of conduction electrons.

  • It increases because there is an increase in the number of conduction electrons.

  • It decreases because the amplitude of lattice vibrations decreases.

  • It increases because the amplitude of lattice vibrations increases.

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