હાઈડ્રોજન પરમાણુ માટે બોહરની દ્વિતીય કક્ષાની ત્રિજ્યા .......... \(\mathop A\limits^o \). (પ્લાંક અચળાંક \( h = 6. \times 10^{-34}\, Js\,;\) ઇલેક્ટ્રોનનું દળ \(= 9.1091 \times 10^{-31}\, kg\,;\) ઇલેક્ટ્રોનનો વિજભાર \(e= 1.60210 \times 10^{-19}\, C\,;\) શૂન્યાવકાશની પારગમ્યતા \(\epsilon _0 = 8.854185 \times 10^{-12} \,kg^{-1} \,m^{-3} A^2\))

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.