A) \[240\]
B) \[120\]
C) \[60\]
D) \[zero\]
Correct Answer: C
Solution :
Einstein by his theory of relativity proved that mass and energy are related to each other and every substance has energy due to its mass also. If a substance loses an amount \[n=4\,\,to\,\,n=1\] of its mass, an equivalent amount \[{{f}_{e}}\] of energy is produced, where \[{{f}_{t}}\] This is called Einstein?s mass energy relation. \[\frac{1}{{{f}_{a}}}=\left( _{a}{{n}_{g}}-1 \right)\left( \frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}} \right)\]Dimension of mass \[\frac{1}{{{f}_{l}}}=\left( _{l}{{n}_{g}}-1 \right)\left( \frac{1}{{{R}_{1}}}-\frac{1}{{{R}_{2}}} \right)\] Alternative : Putting the dimensions of energy and velocity, we get \[_{a}{{n}_{g}}\] \[_{l}{{n}_{g}}\] \[\therefore \] \[\frac{{{f}_{l}}}{{{f}_{a}}}=\frac{_{a}{{n}_{ & g}}-1}{_{l}{{n}_{g}}-1}=\frac{_{a}{{n}_{g}}-1}{\left( \frac{_{a}{{n}_{g}}}{_{a}{{n}_{l}}}-1 \right)}\] \[{{f}_{a}}=15\,cm,\,{{\,}_{a}}{{n}_{g}}=1.5,{{\,}_{a}}{{n}_{l}}=\frac{4}{3}\]You need to login to perform this action.
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