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asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Match the Column I (graph) with Column II (relation) and select the correct answer from the codes given below. Column I Column II A. p. Temperature dependence of resistivity for a typical semiconductor. B. q. Resistivity p of copper as a function of temperature T. C. r. Resistivity `rho` of nichrome as a function of absolute temperature T .

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: A wire carrying an electrical current has no electric field inside it. Reason: Rate of flow of electrons in one direction is equal to the rate of flow of protons in opposite

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: In electrostatics, all charges whether free or bound are considered to be at rest.Reason: The charges in motion constitute an electric

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: A current flows in a conductor only when there is an electric field within the conductor. Reason: The drift velocity of electrons in presence of electric field

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: Charge carriers do not move with acceleration but with a steady drift velocity. Reason: Charge carriers undergo collisions with ions and atoms during

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: Manganin and constantan are widely used in standard resistors. Reason: For manganin and constantan resistance, values would change very little with

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: If a current is flowing through a conducting wire of non-uniform cross-section, drift speed and resistance both will increase at a section where cross-sectional area is loss. Reason: Current density at such sections is more, where cross-sectional area is

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: The drift velocity of electrons in a metallic wire decreases, when temperature of the wire increases. Reason: On increasing temperature, conductivity of metallic wire

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: The average time of collisions `x` decreases with increasing temperature. Reason: At increased temperature, average speed of the electrons, which act as the carriers of current increases, resulting in more frequent

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: If we bend an insulating wire, the resistance of the wire increases.Reason: The drift velocity of electron in bended wire does not remains

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: Bulb generally get fused when they are switched ON or OFF. Reason: When we switch ON or OFF, a circuit current changes it

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: Terminal voltage of a cell is greater than emf of cell during charging the cell. Reason: The emf of a cell is always greater than its terminal

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Assertion: A potentiometer is preferred over a voltmeter for measurement of a cell. Reason: Potentiometer does not draw any current from the

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Resistance and Resistivity The materials can be classified as conductors, semiconductors and insulators depending on their resistivities, in an increasing order of their values. Metals have low resistivities in the range of `10^(-8)Omegam` to `10^(-6)Omegam`. At the other end are insulators like ceramic, rubber and plastics having resistivities `10^(18)` times greater than metals or more. In between these two are the semiconductors. These however, have resistivities characteristically decreasing with a rise in temperature. The resistivities of semiconductors can be decreased by adding small amount of suitable impurities. This last feature is exploited in use of semiconductors for electronic devices.Commercially produced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Resistance and Resistivity The materials can be classified as conductors, semiconductors and insulators depending on their resistivities, in an increasing order of their values. Metals have low resistivities in the range of `10^(-8)Omegam` to `10^(-6)Omegam`. At the other end are insulators like ceramic, rubber and plastics having resistivities `10^(18)` times greater than metals or more. In between these two are the semiconductors. These however, have resistivities characteristically decreasing with a rise in temperature. The resistivities of semiconductors can be decreased by adding small amount of suitable impurities. This last feature is exploited in use of semiconductors for electronic devices.Commercially produced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Resistance and Resistivity The materials can be classified as conductors, semiconductors and insulators depending on their resistivities, in an increasing order of their values. Metals have low resistivities in the range of `10^(-8)Omegam` to `10^(-6)Omegam`. At the other end are insulators like ceramic, rubber and plastics having resistivities `10^(18)` times greater than metals or more. In between these two are the semiconductors. These however, have resistivities characteristically decreasing with a rise in temperature. The resistivities of semiconductors can be decreased by adding small amount of suitable impurities. This last feature is exploited in use of semiconductors for electronic devices.Commercially produced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Resistance and Resistivity The materials can be classified as conductors, semiconductors and insulators depending on their resistivities, in an increasing order of their values. Metals have low resistivities in the range of `10^(-8)Omegam` to `10^(-6)Omegam`. At the other end are insulators like ceramic, rubber and plastics having resistivities `10^(18)` times greater than metals or more. In between these two are the semiconductors. These however, have resistivities characteristically decreasing with a rise in temperature. The resistivities of semiconductors can be decreased by adding small amount of suitable impurities. This last feature is exploited in use of semiconductors for electronic devices.Commercially produced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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Resistance and Resistivity The materials can be classified as conductors, semiconductors and insulators depending on their resistivities, in an increasing order of their values. Metals have low resistivities in the range of `10^(-8)Omegam` to `10^(-6)Omegam`. At the other end are insulators like ceramic, rubber and plastics having resistivities `10^(18)` times greater than metals or more. In between these two are the semiconductors. These however, have resistivities characteristically decreasing with a rise in temperature. The resistivities of semiconductors can be decreased by adding small amount of suitable impurities. This last feature is exploited in use of semiconductors for electronic devices.Commercially produced

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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EMF of a CellAn electric cell is a source of energy that maintains a continuous flow of charge in a circuit. It changes chemical energy into electrical energy. It has two electrodes, positive electrode and negative electrode as shown below.Electric cell has to do some work in maintaining the current through a circuit. The work done by the cell in moving unit positive charge through the whole circuit (including the cell) is called the electromotive force (emf) of the cell. When two electrodes (positive and negative) of a cell are immersed in an electrolytic solution, the charges are exchanged

asked Mar 20, 2022 in 12th Physics by varun (6.7k points)

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