Explanation:
As the work-function of the metal is
$\frac{\text{hc}}{\lambda_0}$, its threshold wavelength is $\lambda_0.$For photoelectric effect, the wavelength of the incident light should be less than or equal to the threshold wavelength of the metal on which light is incident.
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Assertion : If three capacitors of capacitance C1 < C2 < C3 are connected in parallel then their equivalent capacitance Cp > Cs
Reason : 
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(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
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(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
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(c) If assertion is true but reason is false. |
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(d) If the assertion and reason both are false. |
Effective capacitance between A and B in the figure shown is (all capacitance are in mF)
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(a) 21 mF |
(b) 23 mF |
(c) |
(d) |
α - particles of energy 400 KeV are bombarded on nucleus of 
. In scattering of α - particles, its minimum distance from nucleus will be
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(a) 0.59 nm |
(b) 0.59 Å |
(c) 5.9 pm |
(d) 0.59 pm |
By ammeter, which of the following can be measured
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(a) Electric potential |
(b) Potential difference |
(c) Current |
(d) Resistance |
A vertical wire kept in Z-X plane carries a current from Q to P (see figure). The magnetic field due to current will have the direction at the origin O along
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(a) OX |
(b) |
(c) OY |
(d) |
The internal resistance of a cell is the resistance of
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(a) Electrodes of the cell |
(b) Vessel of the cell |
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(c) Electrolyte used in the cell |
(d) Material used in the cell |
