1
JEE Main 2021 (Online) 17th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
Which level of the single ionized carbon has the same energy as the ground state energy of hydrogen atom?
A
8
B
6
C
1
D
4
2
JEE Main 2021 (Online) 17th March Morning Shift
MCQ (Single Correct Answer)
+4
-1
Change Language
An electron of mass m and a photon have same energy E. The ratio of wavelength of electron to that of photon is : (c being the velocity of light)
A
$${1 \over c}{\left( {{{2m} \over E}} \right)^{1/2}}$$
B
$${1 \over c}{\left( {{E \over {2m}}} \right)^{1/2}}$$
C
$${\left( {{E \over {2m}}} \right)^{1/2}}$$
D
$$c{(2mE)^{1/2}}$$
3
JEE Main 2021 (Online) 17th March Morning Shift
Numerical
+4
-1
Out of Syllabus
Change Language
For VHF signal broadcasting, ___________ km2 of maximum service area will be covered by an antenna tower of height 30 m, if the receiving antenna is placed at ground. Let radius of the earth be 6400 km. (Round off to the Nearest Integer) (Take $$\pi$$ as 3.14)
Your input ____
4
JEE Main 2021 (Online) 17th March Morning Shift
Numerical
+4
-1
Change Language
The radius in kilometer to which the present radius of earth (R = 6400 km) to be compressed so that the escape velocity is increased 10 times is ___________.
Your input ____
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