Tag: physics

Quizzes (598) Questions (13441)

Questions Related to physics

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

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

  1. noise introduced in the system

  2. distortion in the system

  3. both (A) and (B)

  4. neither (A) nor (B)
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

Which of the following is not a part of receiver?

  1. Receiving antenna

  2. Amplifier

  3. Modulator

  4. Demodulator
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. video frequency

  2. audio frequency

  3. very high frequency

  4. very low frequency
Reveal answer Fill a bubble to check yourself
A Correct answer
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

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

The RF channel in a radio transmitter produces :

  1. Audio signals

  2. Both audio signal and high frequency carrier waves

  3. High frequency carrier waves

  4. Low frequency carrier waves
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

The range of frequency of audio signal is __________.

  1. $20 Hz$ to $20 MHz$

  2. $0$ to $2 kHz$

  3. $20 Hz$ to $20 kHz$

  4. $20 kHz$ to $200 kHz$
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

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

  1. 111.8 MHz

  2. 113 MHz

  3. 121.6 MHz

  4. 132 MHz
Reveal answer Fill a bubble to check yourself
B Correct answer
Explanation

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

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

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

  1. Heat is a form of energy

  2. Water can boil itself

  3. Water develops heat on its own

  4. None of the above
Reveal answer Fill a bubble to check yourself
A Correct answer
Explanation

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

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

Heat, as a form of energy, flows from

  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
Reveal answer Fill a bubble to check yourself
C Correct answer
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.

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

Amount of heat energy present is determined by :

  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
Reveal answer Fill a bubble to check yourself
A Correct answer
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.