# IGCSE Physics Paper-1: Specimen Questions with Answers 71 - 73 of 149

## Question 71

### Question

MCQ▾

A man tunes his radio from 10 to 60. What does the 60 explain?

Choice (4)

a.

its speed

b.

its amplitude

c.

its wavelength

d.

its frequency

b.

### Explanation

Here man turns his radio from 10 to 60.

Unit of frequency is Hz or 1/s, unit of speed is and unit of wavelength is meter.

Only amplitude is unit less. So man turns amplitude of radio

## Question 72

### Question

MCQ▾

Explain graph between potential difference and current, known that potential difference changes with changes in current through the wire.

Choice (4)

a.

b.

c.

d.

d.

### Explanation

From Ohm՚s Law graph of current vs potential difference is always straight line passing throw origin.

If p. d is zero, current will also zero.

## Question 73

### Question

MCQ▾

Find the amount of sample left after 20 hours if the half-life is 5 hours and has 0.48g of the substance.

Choice (4)

a.

1.92 g

b.

7.68 g

c.

0.03 g

d.

0.12 g