## Download our App

### JEE Mains Previous Years Questions with Solutions

4.5
star star star star star
(100k+ download)
1

### AIEEE 2010

MCQ (Single Correct Answer)
A nucleus of mass $M+$$\Delta m is at rest and decays into two daughter nuclei of equal mass {M \over 2} each. Speed of light is c. The speed of daughter nuclei is A c{{\Delta m} \over {M + \Delta m}} B c\sqrt {{{2\Delta m} \over M}} C c\sqrt {{{\Delta m} \over M}} D c\sqrt {{{\Delta m} \over {M + \Delta m}}} ## Explanation By conservation of energy, \left( {M + \Delta m} \right){c^2} = {{2M} \over 2}{c^2} + {1 \over 2}.{{2M} \over 2}{v^2}, where v is the speed of the daughter nuclei \Rightarrow \Delta m{c^2} = {M \over 2}{v^2} \therefore v = c\sqrt {{{2\Delta m} \over M}} 2 ### AIEEE 2010 MCQ (Single Correct Answer) A nucleus of mass M+$$\Delta m$ is at rest and decays into two daughter nuclei of equal mass ${M \over 2}$ each. Speed of light is $c.$

The binding energy per nucleon for the parent nucleus is ${E_1}$ and that for the daughter nuclei is ${E_2}.$ Then

A
${E_2} = 2{E_1}$
B
${E_1} > {E_2}$
C
${E_2} > {E_1}$
D
${E_1} = 2{E_2}$

## Explanation

In nuclear fission, the binding energy per nucleon of daughter nuclei is greater than the parent nucleon of daughter nuclei is greater than the parent nucleus.
3

### AIEEE 2009

MCQ (Single Correct Answer)

The above is a plot of binding energy per nucleon ${E_b},$ against the nuclear mass $M;A,B,C,D,E,F$ correspond to different nuclei. Consider four reactions :
\eqalign{ & \left( i \right)\,\,\,\,\,\,\,\,\,\,A + B \to C + \varepsilon \,\,\,\,\,\,\,\,\,\,\left( {ii} \right)\,\,\,\,\,\,\,\,\,\,C \to A + B + \varepsilon \,\,\,\,\,\,\,\,\,\, \cr & \left( {iii} \right)\,\,\,\,\,\,D + E \to F + \varepsilon \,\,\,\,\,\,\,\,\,\,\left( {iv} \right)\,\,\,\,\,\,\,\,\,F \to D + E + \varepsilon ,\,\,\,\,\,\,\,\,\,\, \cr}

where $\varepsilon$ is the energy released? In which reactions is $\varepsilon$ positive?

A
$(i)$ and $(iii)$
B
$(ii)$ and $(iv)$
C
$(ii)$ and $(iii)$
D
$(i)$ and $(iv)$

## Explanation

For $A + B \to C + \varepsilon ,\,\,\varepsilon$ is positive. This is because ${E_b}$

for $C$ is greater than the ${E_b}$ for $A$ and $B$.

Again for $F \to D + E + \varepsilon ,\varepsilon$ is positive. This is

because ${E_b}$ for $D$ and $E$ is greater than ${E_b}$ for $F.$
4

### AIEEE 2009

MCQ (Single Correct Answer)
The transition from the state $n=4$ to $n=3$ in a hydrogen like atom result in ultra violet radiation. Infrared radiation will be obtained in the transition from :
A
$3 \to 2$
B
$4 \to 2$
C
$5 \to 4$
D
$2 \to 1$

## Explanation

It is given that transition from the state $n=4$ to $n=3$ in a hydrogen like atom result in ultraviolet radiation. For infrared radiation the energy gap should be less. The only option is $5$ $\to 4.$

### Joint Entrance Examination

JEE Advanced JEE Main

### Graduate Aptitude Test in Engineering

GATE CSE GATE ECE GATE ME GATE PI GATE EE GATE CE GATE IN

NEET

Class 12