# IGCSE Physics Paper-1: Specimen Questions with Answers 38 - 40 of 149

## Question 38

### Question

MCQ▾

Find order of weight of 3 children on the see saw. Three Children Comparing Their Weights Using See-Saw

Which of the following is correct order of the children՚s weights?

Choice (4)

a.

b.

c.

d.

d.

### Explanation

Here from given figure one can conclude that

From first figure in weight Y > Z

From second figure Y > X

And from third figure Z > X

So, from all three results one can write

## Question 39

### Question

MCQ▾

What is the ratio of the primary turns to the secondary turns for a transformer with input 400000 V and output of 20000 V?

Choice (4)

a.

20: 1

b.

1: 20

c.

1: 200

d.

1: 2

a.

### Explanation

Here and are given.

Primary turn = ,

Secondary turn =

The ratio of turns of primary coils and turns of secondary coil is given as,

## Question 40

### Question

MCQ▾

Hydro-electric power station converts which form of energy?

Choice (4)

a.

falling water

b.

oil

c.

hot rocks

d.

waves

a.

### Explanation

The basic principle of hydro-electric is convert kinetic energy to electric energy. And here kinetic energy is obtained from falling water. Thus falling water is the source of energy converted by a hydro-electric power station.