The maximum energy is present in any electron at

Assume that the radius of the first Bohr orbit of hydrogen atom is $0.6 \mathring{A}$. The radius of the third Bohr orbit of $He^{+}$ is $..................$ picometer. (Nearest Integer)

$A$ bulb emits monochromatic yellow light of the wavelength $0.57 \ \mu m$. If the rate of emission of quanta per second of the bulb is $14.33 \times 10^{19}$, the power of the bulb (in $Watt$) is $.....$

$A$ bulb emits light of wavelength $4500 \ \mathring{A}$. The bulb is rated at $150 \ \text{W}$ and $8\%$ of the energy is emitted as light. How many photons are emitted by the bulb per second?

Alpha-particles that come closer to the nucleus:

Calculate the energy in joule corresponding to light of wavelength $45 \ nm$. (Planck's constant,$h = 6.63 \times 10^{-34} \ J \ s$,speed of light,$c = 3 \times 10^8 \ m \ s^{-1}$)