In the nuclear reaction  ${}_{85}{}^{297}\mathrm{X}\to \mathrm{Y}+4\mathrm{\alpha }$, Y is 

1. ${}_{76}\mathrm{Y}_{287}$            

2. ${}_{77}\mathrm{Y}_{285}$

3. ${}_{77}\mathrm{Y}_{281}$             

4. ${}_{77}\mathrm{Y}_{289}$

Thermal neutrons can cause fission in 

(1) ${\mathrm{U}}^{235}$          

(2) ${\mathrm{U}}^{238}$

(3) ${\mathrm{Pu}}^{238}$        

(4) ${\mathrm{Th}}^{232}$

When neutrons are bombarded on nucleus of ${}_{92}\mathrm{U}_{235}$, the number of emitted neutrons will be 

(1) 1         

(2) 2

(3) 3         

(4) 4

The energy released in a typical nuclear fusion reaction is approximately 

(1) 25 MeV           

(2) 200 MeV

(3) 800 MeV         

(4) 1050 MeV

Which one of the following nuclear reactions is a source of energy in the sun 

(1) ${}_4{}^9\mathrm{Be}+{}_2{}^4\mathrm{He}\to {}_6{}^{12}\mathrm{C}+{}_0{}^{-1}\mathrm{n}$

(2) ${}_2{}^3\mathrm{He}+{}_2{}^3\mathrm{He}\to {}_2{}^4\mathrm{He}+{}_1{}^1\mathrm{H}+{}_1{}^1\mathrm{H}$

(3) ${}_{56}{}^{144}\mathrm{Ba}+{}_{56}{}^{92}\mathrm{Kr}\to {}_{92}{}^{235}\mathrm{U}+{}_0{}^{-1}\mathrm{n}$

(4) ${}_{26}{}^{56}\mathrm{Fe}+{}_{48}{}^{112}\mathrm{Ca}\to {}_{74}{}^{167}\mathrm{W}+{}_0{}^{-1}\mathrm{n}$

Which of these is a fusion reaction 

(1) ${}_1{}^3\mathrm{H}+{}_1{}^2\mathrm{H}\to {}_2{}^4\mathrm{He}+{}_0{}^1\mathrm{n}$

(2) ${}_{92}{}^{238}\mathrm{U}\to {}_{82}{}^{206}\mathrm{Pb}+8\left({}_2{}^4\mathrm{He}\right)+6\left({}_{-1}{}^0\mathrm{\beta }\right)$

(3) ${}_7{}^{12}\mathrm{C}\to {}_6{}^{12}\mathrm{C}+{\mathrm{\beta }}^{+}+\mathrm{\gamma }$

(4) None of these

In a nuclear fission reaction 

(1) Two light nuclei combine to produce a heavier nucleus

(2) A light nucleus bombarded by thermal neutrons breaks up

(3) A heavy nucleus bombarded by thermal neutrons breaks up

(4) A heavy nucleus breaks up by itself

Hydrogen bomb is based on which of the following phenomenon

(1) Nuclear fission             

(2) Nuclear fusion

(3) Radioactive decay       

(4) None of these

The number of neutrons released when ${}_{92}\mathrm{U}_{235}$ undergoes fission by absorbing ${}_0{}^1\mathrm{n}$ and $\left({}_{56}{}^{144}\mathrm{Ba}+{}_{36}{}^{89}\mathrm{Kr}\right)$are formed, is 

(1) 0           

(2) 1

(3) 2         

(4) 3

Which of the following particle has similar mass to electron

(1) Proton             

(2) Neutron

(3) Positron           

(4) Neutrino