Tag: physics

Questions Related to physics

During the process of transmission and reception, the signal gets deteriorated due to

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. noise introduced in the system

  2. distortion in the system

  3. both (A) and (B)

  4. neither (A) nor (B)

Show answer
Correct Option: C
Explanation:

Noise is the unwanted energy and distortion both occurring at various stage of a system leads to deterioration of signal, as signal to noise ratio becomes so poor that signal becomes unintelligible and useless.

Which of the following is not a part of receiver?

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. Receiving antenna

  2. Amplifier

  3. Modulator

  4. Demodulator

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Correct Option: C
Explanation:

A receiver receives the pre-modulated signal through receiving antenna, demodulates it using demodulator, and finally amplifies it to be sent as output to loudspeaker etc.

In television transmission, the light from the object is converted into signals called:

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. video frequency

  2. audio frequency

  3. very high frequency

  4. very low frequency

Show answer
Correct Option: A
Explanation:

The Range of frequency for the signals which is used for transmitting videos is called video frequency or VF frequency bandwidth .It ranges between 0 and the highest frequency used to transmit a live telivision image

The RF channel in a radio transmitter produces :

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. Audio signals

  2. Both audio signal and high frequency carrier waves

  3. High frequency carrier waves

  4. Low frequency carrier waves

Show answer
Correct Option: C
Explanation:

When audio signals are transmitted over thousands of kilometres through radio transmission, the audio frequencies that lie within the frequency range of 15 Hertz to 20 KiloHertz has very small signal power and thus cannot be transmitted via antenna for communication purposes. The radiation of electrical energy is only possible at frequencies above 20 KiloHertz.  Thus, the audio signals must be sent along with the high frequency signals for communication since the high frequency signals can travel long distance without dissipation in power. This can be done by superimposing electrical audio signals on a high frequency wave called the carrier wave by a process called modulation.

The range of frequency of audio signal is __________.

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. $20 Hz$ to $20 MHz$

  2. $0$ to $2 kHz$

  3. $20 Hz$ to $20 kHz$

  4. $20 kHz$ to $200 kHz$

Show answer
Correct Option: C
Explanation:

The generally accepted standard range of audible frequencies is $20 Hz$ to $20,000 Hz$, although the range of frequencies individuals hear is greatly influenced by environmental factor. Frequencies below $20 Hz$ are generally felt rather than heard, assuming the amplitude of the vibration is great enough. Frequencies above $20,000 Hz$ ($20 kHz$) frequencies are the first to be affected by hearing loss due to age and prolonged exposure to very loud noises.

What will be the image frequency of an FM radio receiver that is tuned to 91.6 MHz broadcast station?

physics communication system commonly used terms in electronic communication system elements of communication system electromagnetic waves and communication system

  1. 111.8 MHz

  2. 113 MHz

  3. 121.6 MHz

  4. 132 MHz

Show answer
Correct Option: B
Explanation:

Tuned frequency is $91.6MHz$ and corresponding oscillator frequency is $102.3MHz$. Then image frequency is $102.3+10.7 MHz = 113MHz$

When you heat the water in a pot, it boils. What do you infer from above observation?

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Heat is a form of energy

  2. Water can boil itself

  3. Water develops heat on its own

  4. None of the above

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Correct Option: A
Explanation:

Boiling of water requires energy. Therefore heat is a form of energy since it makes the water particles to move and do work.

When we push a huge block, our body becomes

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Hot

  2. Cold

  3. Charged

  4. Smaller

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Correct Option: A
Explanation:

When we push a huge rock, there is no transfer of muscular energy to the stationary rock.  

Also, there is no loss of energy because muscular energy transferred into heat energy, which causes our body to become hot.

Heat, as a form of energy, flows from

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. a body of higher heat content to that of a lower heat content

  2. a body of lower heat content to that of a higher heat content

  3. a hot body to a cold body

  4. a cold body to a hot body

Show answer
Correct Option: C
Explanation:

Heat flows from a hot body to a cold body. Heat flow has nothing to do with the total heat content of the body.

Amount of heat energy present is determined by :

physics heat energy transfers heat energy heat, internal energy and work internal energy

  1. Sum total of kinetic energy and the potential energy of its molecules

  2. Sum total of mechanical energy and surface energy of its molecules

  3. Sum total of chemical energy and potential energy of its molecules

  4. All

Show answer
Correct Option: A
Explanation:

The amount of heat energy present in a body is determined by the sum total of the kinetic energy and potential energy of its molecules.