CIE Physics Paper-1: Specimen Questions 83 - 85 of 109

Question number: 83

MCQ▾

Question

A stopwatch is used to note time of a race is shown in figure. How long did the race take?

Stopwatch used in race with start and end given

Stopwatch used in race with start and end given

The start time and end time of the race are shown in figure by stopwatch.

Choices

Choice (4) Response
a.

45.7s

b.

46.5s

c.

47.0 s

d.

46.0s

Answer

d.

Explanation

From above figure, we can note down the start time is 0.5 s and end time is 46.5 s. Therefore race time is given as,

Theracetime(t)=Endtime(te)starttime(ts)

t=46.50.5

t=46s

Question number: 84

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.

Choices

Choice (4) Response
a.

1.76 g

b.

0.12 g

c.

7.68 g

d. 0.03 g

Answer

a.

Explanation

Here from given data

τ=8hr

Elapsedtime(t)=18hr

Finalamount(mf)=0.37gm

Formula of half-life is given as,

mf=mi(12)tτ

0.37=mi(12)188

mi=1.76gm

Question number: 85

MCQ▾

Question

How we find density of a regularly-shaped block?

Choices

Choice (4) Response
a.

a measuring cylinder and a ruler

b.

a balance and a force meter (spring balance)

c.

a measuring cylinder and a beaker

d.

a balance and a ruler

Answer

d.

Explanation

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

Density=massVolume

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.

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