A charged particle having drift velocity of 7.5× 10^-4 m/s in an electric field of 3×10^-10V/m, has mobility in m^2 V^-1 s^-1

 [NEET-2020 ] a. 2.25×10^15      b. 25×10^6      c. 2.5×19^-6        d. 2.25 ×10^-15

1 g of hydrogen is converted into 0.993 g of helium in a thermonuclear reaction. The energy released is

 [EAMCET (Med.) 1995; CPMT 1999] (a) 63 * 10 7 J        (b) 63 * 10 10 J        (c) 63 * 10 14 J       (d) 63 * 10 20 J

FOR WHICH ONE OF THE FOLLOWING, BOHR MODEL IS NOT VALID ?

 (a) Hydrogen atom             (b) Singly ionised helium atom (He+)               (c) Deuteron atom                (d) Singly ionised neon...