The similarity between the sound waves and light waves is
|
(a) Both are electromagnetic waves |
|
(b) Both are longitudinal waves |
|
(c) Both have the same speed in a medium |
|
(d) They can produce interference |
(d) They can produce interference
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For the given circuit of PN-junction diode, which of the following statement is correct
|
(a) In forward biasing the voltage across R is V |
|
(b) In forward biasing the voltage across R is 2V |
|
(c) In reverse biasing the voltage across R is V |
|
(d) In reverse biasing the voltage across R is 2V |
The electrons are emitted in the photoelectric effect from a metal surface
|
(a) Only if the frequency of the incident radiation is above a certain threshold value |
|
(b) Only if the temperature of the surface is high |
|
(c) At a rate that is independent of the nature of the metal |
|
(d) With a maximum velocity proportional to the frequency of the incident radiation |
Three capacitors are connected to D.C. source of 100 volts shown in the adjoining figure. If the charge accumulated on plates of 
and 
are 
and 
respectively, then
|
(a) |
(b) |
|
(c) |
(d) |
On increasing the number of electrons striking the anode of an X-ray tube, which one of the following parameters of the resulting X-rays would increase
| (a) Penetration power | (b) Frequency | (c) Wavelength | (d) Intensity |
A piece of wire of resistance 4 ohms is bent through 180° at its mid point and the two halves are twisted together, then the resistance is
|
(a) 8 ohms |
(b) 1 ohm |
(c) 2 ohms |
(d) 5 ohms |
Which of the following phenomena suggests the presence of electron energy levels in atoms
|
(a) Radio active decay |
(b) Isotopes |
|
(c) Spectral lines |
(d) a -particles scattering |
