Q50. DNA molecule contains 4 bases whose structure are shown below. One of the structures is not correct, identify the incorrect base structure.
(1)\\
\includegraphics[alt={}]{smile-d3a8de80e3f926d24607dcd4dbb62cbbf86b42b7}
(2)\\
\includegraphics[alt={}]{smile-b477f541ed9d3139097c20e7f95578c9787c3ed4}
(3)\\
\includegraphics[alt={}]{smile-0a8f3eb665e54ed01b416375d7021f0fcd26bc8e}
(4)\\
\includegraphics[alt={}]{smile-04e5fc1ee1f22bd80f73ad5543425d7c19a87eb6}
Q51.Frequency of the de-Broglie wave of electron in Bohr's first orbit of hydrogen atom is $\_\_\_\_$ $\times 10 ^ { 13 } \mathrm {~Hz}$ (nearest integer).\\[0pt]
[Given : $\mathrm { R } _ { \mathrm { H } } ($ Rydberg constant $) = 2.18 \times 10 ^ { - 18 } \mathrm {~J} , h$ (Plank's\\
constant) $= 6.6 \times 10 ^ { - 34 }$ J.s.]\\