Question

To reduce noise pollution, which of the following devices must be installed on the vehicles?
A. Lights
B. Speedometer
C. Horn
D. Silencer

Answer 1

Hint: Read and understand the meaning along with the uses of the given options. Then you will understand which one can be used to reduce the noise pollution produced by the vehicles. The fuel used in vehicles is under combustion, which produces a lot of sound.

Complete step-by-step answer:
Almost all of the people in our world travel by the means of transport like cars, bikes, trains and buses. These vehicles work on the principles of gases and heat engines.
We all know that a vehicle has an engine inside it due to which the wheels of the vehicle rotate when we accelerate the vehicles. The working substance in a vehicle is gas. The petrol or diesel that we put in our vehicle is converted into gas. Then the gas is taken through different processes due which the gas does some work.
This work done is used to rotate the wheels of the vehicle. However, when the gas or the fuel under combustion, a lot of the loud sound is produced. This causes noise pollution.
In order to reduce the noise produced in vehicles, a silencer is used. A silencer is a long tube that works as an exhaust too. The smoke and sound is taken out through the silencer.
There are different types of the silencers depending on their features. For example, one way to reduce the noise is by using materials that are absorbent of sound. These materials are present in the silencer.

So, the correct answer is “Option D”.

Note: Let us discuss the uses of the other option.
(i) Light in vehicles helps the rider to the objects and the vehicles in the surrounding.
(ii) Speedometer is a device present in a vehicle that reads the instantaneous speed of the vehicle.
(iii) Horn is an instrument to produce a quick sound to indicate something to the person in front of our vehicle. However, excess horning is one of the reasons for noise pollution.