1
JEE Main 2016 (Online) 9th April Morning Slot
+4
-1
When photons of wavelength $${\lambda _1}$$ are incident on an isolated sphere, the corresponding stopping potential is found to be V. When photons of wavelength $${\lambda _2}$$ are used, the corresponding stopping potential was thrice that of the above value. If light of wavelength $${\lambda _3}$$ is used then find the stopping potential for this case :
A
$${{hc} \over e}\left[ {{1 \over {{\lambda _3}}} - {1 \over {{\lambda _2}}} - {1 \over {{\lambda _1}}}} \right]$$
B
$${{hc} \over e}\left[ {{1 \over {{\lambda _3}}} + {1 \over {{\lambda _2}}} - {1 \over {{\lambda _1}}}} \right]$$
C
$${{hc} \over e}\left[ {{1 \over {{\lambda _3}}} + {1 \over {2{\lambda _2}}} - {3 \over {2{\lambda _1}}}} \right]$$
D
$${{hc} \over e}\left[ {{1 \over {{\lambda _3}}} + {1 \over {2{\lambda _2}}} - {1 \over {{\lambda _1}}}} \right]$$
2
JEE Main 2016 (Offline)
+4
-1
Radiation of wavelength $$\lambda ,$$ is incident on a photocell. The fastest emitted electron has speed $$v.$$ If the wavelength is changed to $${{3\lambda } \over 4},$$ the speed of the fastest emitted electron will be:
A
$$= v{\left( {{4 \over 3}} \right)^{{1 \over 2}}}$$
B
$$= v{\left( {{3 \over 4}} \right)^{{1 \over 2}}}$$
C
$$> v{\left( {{4 \over 3}} \right)^{{1 \over 2}}}$$
D
$$< v{\left( {{4 \over 3}} \right)^{{1 \over 2}}}$$
3
JEE Main 2015 (Offline)
+4
-1
Out of Syllabus
Match List - $${\rm I}$$ (Fundamental Experiment) with List - $${\rm II}$$ (its conclusion) and select the correct option from the choices given below the list:

A
$$A - ii;\,\,B - i,\,\,C - iii$$
B
$$A - iv;\,\,B - iii,\,\,C - ii$$
C
$$A - i;\,\,B - iv,\,\,C - iii$$
D
$$A - ii;\,\,B - iv,\,\,C - iii$$
4
JEE Main 2013 (Offline)
+4
-1
The anode voltage of a photocell is kept fixed. The wavelength $$\lambda$$ of the light falling on the cathode is gradually changed. The plate current $$I$$ of the photocell varies as follows :
A
B
C
D
EXAM MAP
Medical
NEET