Let speed of boat in still water and speed of boat in upstream be ‘9x’ km/h and ‘5x’ km/h, respectively. Speed of stream = 9x – 5x = 4x km/h Speed of boat in downstream = 9x + 4x = 13x km/h So, 13x = 390/5 = 78 Or, x = 6 Speed of boat in still water = 9 × 6 = 54 km/h Desired time = 18/54 = 20 minutes
Which of the following is an example of longitudinal waves in a gas medium?
Which of the following statement is correct?
I. Magnetite is a natural magnet
II. A freely suspended magnet always aligns in N-S direction
Specific resistance of a conductor increases with :
The rate of change of which of the following determines angular velocity?
Which quantity has the same dimensional formula as impulse?
Which of the following statement is true for a wavelength of 1000 nm. A p-n photodiode is fabricated from a semiconductor with band gap of 1.9 eV.
Global warming is expected to result in
The absolute temperature of a body A is five times that of another body B. For two bodies, the difference in wave lengths at which energy radiated is ma...
Which of the following is the best conductor of electricity?
Sensitivity of the human eye is maximum in the –
