Question
Meeta's father was driving her to school. At the traffic signal, she noticed that each traffic light was made of many tiny lights instead of a single bulb. When Meeta asked this question to her father, he explained the reason for this.
Answer the following questions based on above information:
(i) What were the values displayed by Meeta and her father?
(ii) What answer did Meeta's father give?
(iii) What are the tiny lights in traffic signals called and how do these operate?
Solution
i)
The values displayed by Meeta and her father are:
Meeta: Curious mind
Meeta's Father: knowledge and patience
ii)
The answer that Meeta's father had given would be the advantages of using LED lights over a single bulb.
Advantages of LED:
a) LED's consume very less power as compared to an incandescent bulb.
b) The cost of tiny LED is much less than of a bulb. This reduces the maintenance cost of LED bulbs.
c) The working of the traffic will remain unhindered even if one of the bulbs is not working.
iii)
The tiny lights are called LED (Light Emitting Diode) and they work on the principle of de-excitation of electrons in a forward biased semiconductor upon passing electricity through them.
