JEE Main 2017 (Online) 9th April Morning Slot | Atoms and Nuclei Question 248 | Physics

Imagine that a reactor converts all given mass into energy and that it operates at a power level of 10⁹ watt. The mass of the fuel consumed per hour in the reactor will be : (velocity of light, c is 3×10⁸ m/s)

0.96 gm

0.8 gm

4 $$ \times $$ 10^$$-$$2 gm

6.6 $$ \times $$ 10^$$-$$5 gm

JEE Main 2017 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

Two deuterons undergo nuclear fusion to form a Helium nucleus. Energy released in this process is : (given binding energy per nucleon for deuteron = 1.1 MeV and for helium = 7.0 MeV)

30.2 MeV

32.4 MeV

23.6 MeV

25.8 MeV

JEE Main 2017 (Online) 8th April Morning Slot

MCQ (Single Correct Answer)

-1

According to Bohr’s theory, the time averaged magnetic field at the centre (i.e. nucleus) of a hydrogen atom due to the motion of electrons in the n^th orbit is proportional to : (n = principal quantum number)

$${n^{ - 4}}$$

$${n^{ - 5}}$$

n^$$-$$3

n^$$-$$2

JEE Main 2017 (Offline)

MCQ (Single Correct Answer)

-1

Out of Syllabus

A radioactive nucleus A with a half life T, decays into a nucleus B. At t = 0, there is no nucleus B. At sometime t, the ratio of the number of B to that of A is 0.3. Then, t is given by :

$$t = {T \over {\log (1.3)}}$$

$$t = T\log (1.3)$$

$$t = {T \over 2}{{\log 2} \over {\log 1.3}}$$

$$t = T{{\log 1.3} \over {\log 2}}$$

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