Primary 4 Basic Science and Technology Flashcards: Sources, Uses and Reflection of Light Energy

Question 1

What is light energy?

Accepted Answer

energy that enables us to see

Question 2

What is Earth’s main natural source of light?

Accepted Answer

the Sun

Question 3

A candle flame is an example of an ____ source of light.

Accepted Answer

artificial

Question 4

Which produces its own light: the Moon, a mirror, the Sun, or a book?

Accepted Answer

the Sun

Question 5

Why can we see most objects?

Accepted Answer

light reflected from them enters our eyes

Question 6

What is reflection of light?

Accepted Answer

the bouncing back of light from a surface

Question 7

Which surface reflects light best: polished mirror, rough cloth, soil, or cardboard?

Accepted Answer

polished mirror

Question 8

A mirror forms an image by ____ light.

Accepted Answer

reflecting

Question 9

The Moon is visible mainly because it ____ sunlight.

Accepted Answer

reflects

Question 10

Which is NOT a source of light: bulb, candle, Sun, or mirror?

Accepted Answer

mirror

Question 11

Light from a torch helps a person to ____.

Accepted Answer

see in darkness

Question 12

Plants use sunlight to ____.

Accepted Answer

make food

Question 13

Traffic lights use light mainly to ____.

Accepted Answer

give road signals

Question 14

A shadow forms when an opaque object ____ light.

Accepted Answer

blocks

Question 15

A transparent material allows most light to ____.

Accepted Answer

pass through

Question 16

Which material is opaque: clear glass, clean water, cardboard, or air?

Accepted Answer

cardboard

Question 17

The image in a plane mirror appears ____ the mirror.

Accepted Answer

behind

Question 18

The main reason a smooth surface gives a clear image is that it ____.

Accepted Answer

reflects light regularly

Question 19

The correct way to direct sunlight safely is to use a ____.

Accepted Answer

mirror without looking at the Sun

Question 20

Why should a pupil never stare directly at the Sun?

Accepted Answer

its intense light can damage the eyes

Strong work.