Expected Questions for SSC CGL 2017 - Science and Technology

Important Points You need to know

Q. Why is rainbow seen a shower ?

Answers - After a shower the clouds containing water droplets act like a prism through which the white light is dispersed and produces a spectrum. 

Q. Why does an Ordinary pendulum clock loose time during summer ?

Answers- In summer due to high temperature & heat the length of the pendulum increases. For this it increases of duration of each oscillation of the pendulum. Hence the clock looses time during summer.

Q. Why does kerosene oil floats on water ?

Answers - Because the density of kerosene oil is less compared to water. 

Q. Why does an electric bulb explode when it is broken ?

Answers - The bulb is a partial vaccum and as it breaks air rushes in causing a small explosion.

Q. Why is it easier to swim in the sea than in a river ?

Answer - The density of sea water is higher, hence the upthrust is more than that of river water. 

Q. Why Sky appears blue ?

Answers- Violet and blue light have shorter waves and are scattered more than red light waves. While red lights goes almost straight through the atmosphere, blue and violet are scattered by particles in the atmosphere. Thus the sky appears blue. 

Q. Why does a man falls forward when he jumps out of a running train ?

Answers - He is in motion while in the train, when he jumps from the running train, his feet comes to rest while touching the ground but his upper portion of the body which is still in motion for this reasons it takes him forward.

Q.  Why is soft iron used as an electromagnet ?

Answers - Because it remains magnetic only till the current passes through the coil and looses its magnetism when the current is switched off. 

Q. Why is it difficult to breath at higher altitudes ?

Answers - Due to low air pressure at higher altitudes the quantity of air is less and so also that of oxygen, that is why it is difficult to breath at higher altitude. 

Q. Why does Ice floats in water but sinks in alcohol ?

Answers - Ice is lighter than water, it floats on it, where as ice is heavier than alcohol  i.e ice is less denser than water where as ice is more denser than alcohol. for this above reasons ice floats in water & sinks in alcohol.