A Boy can swim 12 km/hr in still water. If the velocity of the stream is 6 km/hr, the time taken by him to swim a place 28 km upstream and back is
Rate downstream = 12 + 6 = 18 km/hr Rate upstream = 12 – 6 = 6 km/hr ∴ Required time = 28/18 + 28/6 = 56/9 = `6(2)/9` hr.
The splitting up of white light into seven colours on passing through a glass prism is called as
Foucault Experiment is the proof of
Twinkling of the Stars is due to the phenomenon of
A ship will submerge when it displaces water equal to its
Which of the following dyes is used for colouring Paper and typewriters?
Which of the following occurs in a positively charged body ------------.
In the atmosphere ultraviolet rays are absorbed by –
The SI unit of Pressure is
Which compound is used to prepare water proof clothes?
A rear-view mirror for driving is –
