Archives

Two sources of light are said to be coherent when both give out light waves of same______

Answer: Two sources of light are said to be coherent when both give out light waves of the same wave length and constant phase difference. Two... View Article

Davisson and Germer experiment proves the

Davisson and Germer experiment is an excellent agreement between the experimental and theoretical value of wavelength of an electron.... View Article

A dielectric develops a _____in an external electric field.

Due to charge separation, a net dipole moment is created.... View Article

If cells are joined in series, they have ________.

same current. Batteries can either be connected in series, parallel or a combination of both. In a series circuit, electrons travel in a single... View Article

Three identical cells, each of 4 V and internal resistance r, are connected in series to a 6 ohm resistor. If the current flowing in the circuit is 2 A. The internal resistance of each cell is

Total emf = 3 x 4 = 12 V Total resistance = 6 + 3r Current in the circuit = 2 A Using ohms law 2 = 12/ (6+3r) 2(6+3r)=12 12+6r=12 6r = 12-12 = 0... View Article

Light from a bulb is falling on a wooden table but no photo electrons are emitted as

It is because the work function of wood is more than the energy of the incident photons of light. Hence, photoelectrons are not emitted from the... View Article

If the internal resistance of a cell is 20 ohm and resistance of the circuit is also 20 ohm. Will the current remain same whether the given n identical cells are in series or in parallel?

Since for same current R = r.... View Article

The velocity of matter waves are__________

Answer: The velocity of the matter-wave is not constant since it depends upon the velocity of the material particle. A matter wave is a wave... View Article

Modes of communication system are classified into :

There are two basic modes of communication : point to point and broadcast.... View Article

The bandwidth sufficient for commercial telephonic communication:

For speech signals (as in telephone) frequency range 300 Hz- 3100 Hz is adequate i.e., a speech signal requires a bandwidth of 2800 Hz.... View Article

In which manner does current or voltage vary in an analog signal with time?

In an analog signal,the amplitude of the signal varies continuously with time.... View Article

Which of the following frequencies will be suitable for the horizontal communication using sky waves?

Waves of frequency 10 MHz will be reflected by the ionosphere and hence can be propagated through sky waves. Waves of 10 KHz cannot be radiated... View Article

Frequencies in the UHF range normally propagates by means of :

UHF (Ultra High Frequency) ranges include frequencies of 100 MHz to few GHz and these waves can neither be propagated by surface nor by the sky... View Article

Four different capacitors are connected in series then

In series, charge on each capacitor is same.... View Article

Figure below shows an unbalanced Wheatstone bridge. What is the direction of conventional current between B and D?

Answer: The potential drop across AD is less than that across AB. So, the potential of D is higher than that of B. Hence, the flow is from D... View Article

Which among the following is a device that converts one form of energy into another :

Transducer is a device that converts a signal in one form of energy into another form. An electric transducer used in communication converts some... View Article

Atomic mass number of an element is 232 and its atomic number is 90. The end products of this radioactive element are an isotope of lead (Atomic mass 208 and atomic number 82). The number of α and β-particle emitted is:

Change in A = 24, hence 6 α - particles are emitted . change in Z = 8 = 6 x 2-4 x 1. That is 4 β-particles are emitted.... View Article

M	T	W	T	F	S	S
				1	2	3
4	5	6	7	8	9	10
11	12	13	14	15	16	17
18	19	20	21	22	23	24
25	26	27	28	29	30