# IGCSE Physics Paper-1: Specimen Questions with Answers 84 - 87 of 149

## Question number: 84

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MCQ▾

### Question

Find the amount of sample left after 18 hours if the half-life is 8 hours and has 0.37 g of the substance.

Choice (4)

a.

0.03 g

b.

7.68 g

c.

1.76 g

d.

0.12 g

c.

### Explanation

Here from given data

Formula of half-life is given as,

## Question number: 85

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### Question

How we find density of a regularly-shaped block?

### Choices

Choice (4)

a.

a measuring cylinder and a beaker

b.

a measuring cylinder and a ruler

c.

a balance and a ruler

d.

a balance and a force meter (spring balance)

c.

### Explanation

Here we want to measure density of regular shape so from formula,

Therefore from measuring mass a balance is used and Volume is measured by ruler.

Ruler is a straight strip with a smooth edge which is use as a guide in drawing straight line. Then we can measure perfect shape

So we should use a balance and a ruler.

## Question number: 86

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MCQ▾

### Question

Find the amount of sample left after 18 hours if the half-life is 8 hours and has 0.37 g of the substance.

Choice (4)

a.

0.12 g

b.

0.03 g

c.

1.76 g

d.

7.68 g

c.

### Explanation

Here from given data

Formula of half-life is given as,

## Question number: 87

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MCQ▾

### Question

The diagram shows a speed-time graph for a body moving with constant acceleration. What is the shaded area under the graph?

Choice (4)

a.

speed

b.

distance

c.

time

d.

acceleration

b.

### Explanation

Here in above figure the graph of speed vs time is given.

Then area under the graph denoted speed ⨯ time.

As we know that speed means velocity

Then in this graph area under the graph is distance.