Physics Practice Question and Answer

Q:

A potentiometer is considered a versatile and accurate device to make an electrical measurement of EMF. Why?

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  • 1
    Because the method involves a combination
    Correct
    Wrong
  • 2
    There are cells involved
    Correct
    Wrong
  • 3
    Because of potential gradients
    Correct
    Wrong
  • 4
    As there is no flow of current through the galvanometer
    Correct
    Wrong
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Answer : 4. "As there is no flow of current through the galvanometer"
Explanation :

A potentiometer is an accurate and versatile device to make electrical measurements of emf because the method involves a condition of no current flow through the galvanometer, the device can be used to measure potential difference, internal resistance of a cell and compare emf's of two sources. Q.

Q:

Degree of dissociation does not depend on which of the following factors?

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  • 1
    Nature of the solute
    Correct
    Wrong
  • 2
    Nature of the solvent
    Correct
    Wrong
  • 3
    Sound
    Correct
    Wrong
  • 4
    Concentration
    Correct
    Wrong
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Answer : 3. "Sound "
Explanation :

The Degree of dissociation does not depend on catalyst.The equivalent conductivity of 0.1M weak acid is 100 times less than that at infinite dilution.

Q:

What is the degree of dissociation for strong electrolytes?

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  • 1
    1
    Correct
    Wrong
  • 2
    0
    Correct
    Wrong
  • 3
    Less than 1
    Correct
    Wrong
  • 4
    Greater than 1
    Correct
    Wrong
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Answer : 1. "1"
Explanation :

Strong electrolytes have a degree of dissociation close to one, while weak electrolytes have a degree of dissociation less than one. Solvent nature: Solvents with a high dielectric constant show more dissociation. Dilution: As the solution is diluted, the degree of dissociation increases.

Q:

Polar satellites are used for high-resolution imaging of the earth’s surface because _____

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  • 1
    They have better cameras
    Correct
    Wrong
  • 2
    They are very high above the surface of the earth and travel slowly to gather more information
    Correct
    Wrong
  • 3
    They are closer to the surface of the earth and can cover vast areas very quickly
    Correct
    Wrong
  • 4
    They can be launched by most countries in the world
    Correct
    Wrong
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Answer : 3. "They are closer to the surface of the earth and can cover vast areas very quickly"
Explanation :

Explanation: Since polar satellites orbit close to the surface of the earth, it is easier to click images of the planet's surface with greater detail. Their high orbital velocity enables them to view most of the surface strip-by-stip very quickly with which high-resolution images can be constructed.

Q:

Most waves used for communication purposes rely on geostationary satellites because _____

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  • 1
    They cannot transmit data at long distances due to curvature of the earth
    Correct
    Wrong
  • 2
    They are reflected by the atmosphere
    Correct
    Wrong
  • 3
    They are very cheap
    Correct
    Wrong
  • 4
    It does not occupy space on the earth’s surface
    Correct
    Wrong
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Answer : 1. "They cannot transmit data at long distances due to curvature of the earth"
Explanation :

Explanation: Most communication waves cannot transmit data accurately over long distances due to the curvature of the earth. They can only do so in the line of sight. However, they are not reflected by the ionosphere like radio waves and can be relayed to a wide area using geostationary satellites.

Q:

If the kinetic energy of a satellite is halved, its orbital radius becomes _____

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  • 1
    ½ times
    Correct
    Wrong
  • 2
    2 times
    Correct
    Wrong
  • 3
    4 times
    Correct
    Wrong
  • 4
    Infinity
    Correct
    Wrong
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Answer : 1. "½ times"
Explanation :

radius of its orbit will become half.

Q:

What are the conditions for gas like Carbon monoxide to obey the ideal gas laws?

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  • 1
    Low temperature and low pressure
    Correct
    Wrong
  • 2
    Low temperature and high pressure
    Correct
    Wrong
  • 3
    High temperature and low pressure
    Correct
    Wrong
  • 4
    High temperature and high pressure
    Correct
    Wrong
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Answer : 3. "High temperature and low pressure "
Explanation :

A real gas can behave as an ideal gas if volume of molecule is negligible and interaction between molecule is negligible. This will happen if number of molecule per unit volume is very small. This is only possible at high temperature and low pressure.

Q:

The observer hears a sound from the source which is moving away from the observer who is stationary. Determine the frequency of the sound

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  • 1
    It is halved
    Correct
    Wrong
  • 2
    It remains the same
    Correct
    Wrong
  • 3
    It reaches infinity
    Correct
    Wrong
  • 4
    It gets doubled
    Correct
    Wrong
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Answer : 1. "It is halved"
Explanation :

If the observer is moving away from the source ((Figure)), the observed frequency can be found: λs=vTo−voTovTs=(v−vo)Tov(1fs)=(v−vo)(1fo)fo=fs(v−vov).


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