- AThe energy necessary to emit electrons from metal surface is 2eV
- BThe energy of electrons emitted from metallic surface is 2eV
- CThe value of photoelectric current is 2eV
- DThe value of threshold frequency is 2eV
Explanation:
By definition the work function is the minimum energy (in electron volts) needed to remove an electron from a solid to a point immediately outside the solid surface (or energy needed to move an electron from the Fermi level into vacuum).
Hence, if the work function of cesium metal is 2ev, it means that the energy necessary to emit electrons from metal surface is 2eV.
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Two tangent galvanometers having coils of the same radius are connected in series. A current flowing in them produces deflections of 60° and 45° respectively. The ratio of the number of turns in the coils is
| (a) 4/3 |
(b) ( |
(c) ( |
(d) |
Assertion : A direct current flows through a metallic rod, produced magnetic field only outside the rod.
Reason : There is no flow of charge carriers inside the rod.
|
(a) If both assertion and reason are true and the reason is the correct explanation of the assertion. |
|
(b) If both assertion and reason are true but reason is not the correct explanation of the assertion. |
|
(c) If assertion is true but reason is false. |
|
(d) If the assertion and reason both are false. |
When X rays pass through a strong uniform magnetic field, Then they
|
(a) Do not get deflected at all |
|
(b) Get deflected in the direction of the field |
|
(c) Get deflected in the direction opposite to the field |
|
(d) Get deflected in the direction perpendicular to the field |
The magnetic flux linked with a coil is given by an equation ∅ (in webers) =
. The induced e.m.f. in the coil at the fourth second will be
|
(a) 16 units |
(b) 39 units |
(c) 67 units |
(d) 145 units |
Inside a hollow charged spherical conductor, the potential
| (a) Is constant |
| (b) Varies directly as the distance from the centre |
| (c) Varies inversely as the distance from the centre |
|
(d) Varies inversely as the square of the distance from the centre |
The carrier frequency generated by a tank circuit containing 1 nF capacitor and 10 mH inductor is
|
(a) 1592 Hz |
(b) 1592 MHz |
(c) 1592 kHz |
(d) 159.2 Hz |