1
JEE Main 2020 (Online) 2nd September Morning Slot
Numerical
+4
-0
When radiation of wavelength $$\lambda$$ is used to illuminate a metallic surface, the stopping potential is V. When the same surface is illuminated with radiation of wavelength 3$$\lambda$$, the stopping potential is $${V \over 4}$$. If the threshold wavelength for the metallic surface is n$$\lambda$$ then value of n will be __________.
2
JEE Main 2020 (Online) 8th January Evening Slot
Numerical
+4
-0
The first member of the Balmer series of hydrogen atom has a wavelength of 6561 Å. The wavelength of the second member of the Balmer series (in nm) is:
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