Physics
A copper wire of radius r and length l has a resistance of R. A second copper wire with radius 2r and length l is taken and the two wires are joined in a parallel combination. The resultant resistance of the parallel combination of the two wires will be

5 R
R/5
4 R/5
5 R/4

ANSWER DOWNLOAD EXAMIANS APP

Physics
A photon of X-ray has energy of 1 keV. A photon of visible radiation has energy of 3 eV. In this context, which one of the following statements is not correct?

The frequency of X-ray photon is higher than the frequency of visible radiation photon.
The speeds of both the photons in vacuum are different
The wavelength of X-ray photon is less than the wavelength of visible radiation photon.
Both the photons have different energies.

ANSWER DOWNLOAD EXAMIANS APP
MORE MCQ ON Physics