1
JEE Advanced 2024 Paper 2 Online
MCQ (Single Correct Answer)
+3
-1
Change Language
A metal target with atomic number $Z=46$ is bombarded with a high energy electron beam. The emission of X-rays from the target is analyzed. The ratio $r$ of the wavelengths of the $K_\alpha$-line and the cut-off is found to be $r=2$. If the same electron beam bombards another metal target with $Z=41$, the value of $r$ will be
A
2.53
B
1.27
C
2.24
D
1.58
2
JEE Advanced 2022 Paper 2 Online
MCQ (Single Correct Answer)
+3
-1
Change Language

When light of a given wavelength is incident on a metallic surface, the minimum potential needed to stop the emitted photoelectrons is $6.0 \mathrm{~V}$. This potential drops to $0.6 \mathrm{~V}$ if another source with wavelength four times that of the first one and intensity half of the first one is used. What are the wavelength of the first source and the work function of the metal, respectively? [Take $\frac{h c}{e}=1.24 \times$ $10^{-6} \mathrm{JmC}^{-1}$.]

A
$1.72 \times 10^{-7} \mathrm{~m}, 1.20 \mathrm{eV}$
B
$1.72 \times 10^{-7} \mathrm{~m}, 5.60 \mathrm{eV}$
C
$3.78 \times 10^{-7} \mathrm{~m}, 5.60 \mathrm{eV}$
D
$3.78 \times 10^{-7} \mathrm{~m}, 1.20 \mathrm{eV}$
3
JEE Advanced 2017 Paper 2 Offline
MCQ (Single Correct Answer)
+3
-0.75
Change Language
A photoelectric material having work-function $${\phi _0}$$ is illuminated with light of wavelength $$\lambda \left( {\lambda < {{he} \over {{\phi _0}}}} \right).$$ The fastest photoelectron has a de-Broglic wavelength $${\lambda _d}.$$ A change in wavelength of the incident light by $$\Delta \lambda $$ result in a change $$\Delta {\lambda _d}$$ in $${\lambda _d}.$$ Then the ratio $$\Delta {\lambda _d}/\Delta \lambda $$ is proportional to
A
$${\lambda _d}/\lambda $$
B
$$\lambda _d^2/{\lambda ^2}$$
C
$$\lambda _d^3/\lambda $$
D
$$\lambda _d^3/{\lambda ^2}$$
4
JEE Advanced 2016 Paper 1 Offline
MCQ (Single Correct Answer)
+3
-1
Change Language
In a historical experiment to determine Planck's constant, a metal surface was irradiated with light of different wavelengths. The emitted photoelectron energies were measured by applying a stopping potential. The relevant data for the wavelength ($$\lambda $$) of incident light and the corresponding stopping potential (V0) are given below:

$$\lambda \left( {\mu m} \right)$$ V0(Volt)
0.3 2.0
0.4 1.0
0.5 0.4


Given that c = 3 $$ \times $$ 108 ms-1 and e = 1.6 $$ \times $$ 10-19 C, Planck's constant (in units of J-s) found from such an experiment is) :
A
6.0 $$ \times $$ 10-34
B
6.6 $$ \times $$ 10-34
C
6.4 $$ \times $$ 10-34
D
6.8 $$ \times $$ 10-34
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