The spectrum of a star’s light is measured and the wavelength of one of the lines as thesodium’s line is found
to be 589 nm. The same line has the wavelength of 497 nm whenobserved in the laboratory. This means the
star is
You lift a heavy book from the floor of the room and keep it in the book-shelf having a height 2 m. In this process
you take 5 seconds. The work done by you will depend upon:
Two charges of equal magnitudes and at a distance r exert a force F on each other. If the charges
are halved and distance between them is doubled, then the new force acting on each charge is:
The distance between the plates of a charged parallel plate capacitor is 4mm and potential
difference is 6 volts. If the distance between the plates is increased to 12mm, then :
A man M1 of mass 80 kg runs up a staircase in 15s. Another man M2 also of mass 80 kg runs up the same staircase in 20s. The ratio of the power developed by them will be
A parallel plate air capacitor is charged and then isolated. When a dielectric material is inserted
between the plates of the capacitor , then which of the following does not change:
If source and observer are moving towards each other with same speed and aftercrossing they are
receding each other then frequency observed by observer:
