In one fission or uranium `3xx10^-11J` of energy is made available. Calculate the total number of fissions necessary per second to generate power of 15 kW.

A potential difference of 3V is applied across a conductor of resistance 1.5 Omega. Calculate the number of electrons flowing through it in one second. Given charge on electron, e=1.6 xx10^(-19)C.

Estimating the following two numbers should be interesting. The first number will tell you why radio engineering do not need to worry much about photons. The second number tells you why our eye can never count photons, even in barely detetable light. The number of photons emitted per second by a MW transmitter of 10 kW power emitting radio waves of wavelength 500 m.

A potential difference of 200 volt is maintained across a conductor of resistance 100ohm. Calculate the number of electrons flowing through it in one second. Charge on electron e = 1.6 xx10^-19C

A potential difference of 3 V is applied across a conductor of resistance 1.5 Omega . Calculate the number of electrons flowing through the conductor in 1 s. Given, charge on electorn , e = 1. xx 10^-19 C

An electron is circulating around the nucleus of a hydrogen ato in a circular orbit of radius 5.3 cxx10^-11 m. Calculate the electric potential energy of the atom in eV. What would be the electric potential due to a helium nucleus at the same radius. Given, that (4piepsilon_0)^-1 = 9xx10^9 m F^-1 and e = 1.6 xx 10^-19 C .

If mass of one atom is 3.32 xx 10^(-23)g, then calculate number of nucleons (neutrons and protons) present in 2 atoms of the element: