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Electric Current through Gases — JEE Main & Advanced Physics PYQs

46 previous year questions from Electric Current through Gases with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

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1

A pure tungsten cathode and a thoriated-tungsten cathode share the same geometrical dimensions and are operated at a common temperature. The current produced by the thoriated-tungs

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Determine the ratio n(T)/n(1000 K ) for a tungsten emitter at temperatures T = 300 K , 2000 K , and 3000 K . Here, n(T) denotes the number of thermions emitted per second by the su

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Within a discharge tube, the mean free path of electrons in the gas is inversely proportional to the internal pressure. The Crookes dark space occupies half the length of the disch

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At 2000 K , the saturation current from a thoriated-tungsten cathode is 100 mA . Determine the saturation current for a pure-tungsten cathode that has the same surface area and ope

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Within a discharge tube filled with a gas, a molecule undergoes ionization, causing an electron to be detached. An electric field of 5.0 kV m ⁻¹ is present in the region of the eve

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Determine the factor by which the emission current changes when the temperature of a tungsten filament is increased from 2000 K to 2010 K . The work function of tungsten is 4.5 eV

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For tungsten, the constant A in the Richardson–Dushman equation is 60 imes 10^4 A m ⁻² K ⁻² , and its work function is 4.5 eV . An electric heater of 24 W is used to heat a tungste

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When the plate voltage is 36 V , the power delivered in the plate circuit of a diode is 1.0 W . Determine the power delivered if the plate voltage is raised to 49 V . Assume the La

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A triode valve operates with V_p = 225 V and V_g = -0.5 V . If the plate voltage is raised to 250 V and the grid voltage is lowered to -2.5 V , the plate current is found to remain

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Determine the amplification factor of a triode valve that has a plate resistance of 2 k and a transconductance of 2 millimho .

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Determine the values of r_p , , and g_m for a triode operating at a plate voltage of 200 V and a grid voltage of -6 V . The plate characteristics are depicted in the figure.

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A triode valve has a dynamic plate resistance of 10 k . Determine the change in the plate current when the plate voltage is altered from 200 V to 220 V .

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A triode has a plate resistance of 8 k and a transconductance of 2.5 millimho . Determine the increase in the plate current if the plate voltage is raised by 48 V while the grid vo

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A triode has a plate resistance of 8 k and a transconductance of 2.5 millimho . The plate voltage is increased by 48 V . If the plate voltage is held constant at this new elevated

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A triode has a plate resistance of 10 k and an amplification factor of 20 . It is operated at a plate voltage of 250 V and a grid voltage of -7.5 V , resulting in a plate current o

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A triode has a plate resistance of 10 k and an amplification factor of 20 . Initially, it is operated at a plate voltage of 250 V and a grid voltage of -7.5 V , yielding a plate cu

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Within a discharge tube filled with a gas, a molecule undergoes ionization, causing an electron to be detached. An electric field of 5.0 kV m ⁻¹ is present in the region of the eve

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Helium at a low pressure is contained within a discharge tube. A large potential difference is applied across this tube. Consider a helium atom that has just been ionized by the de

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Two discharge tubes possess identical material structure and are filled with the same gas. The length of one tube is 10 cm while that of the second tube is 20 cm . Sparking initiat

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For a 6F6 triode tube, the plate current, plate voltage, and grid voltage are related by i_p = 41(V_p + 7 V_g)^ 1.41 , where V_p and V_g are in volts and i_p is in microamperes. If

Concepts Of Physics MCQ Edition [Volume 2] Solution View → 21

For a 6F6 triode tube, the plate current, plate voltage, and grid voltage are related by i_p = 41(V_p + 7 V_g)^ 1.41 , where V_p and V_g are in volts and i_p is in microamperes. If

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The plate current in a triode can be written as i_p = k ! (V_g + V_p )^ 3/2 . The mutual conductance is proportional to what power of the plate current?

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A triode possesses a mutual conductance of 2.0 millimho and a plate resistance of 20 k . To amplify a signal by a factor of 30 , what load resistance must be incorporated into the

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When the load resistance of an amplifier is modified from 4 k to 8 k , its gain factor increases from 10 to 12 . Determine the amplification factor.

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When the load resistance of an amplifier is modified from 4 k to 8 k , its gain factor increases from 10 to 12 . Determine the plate resistance.

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For a diode, the plate current is 20 mA when the plate voltage is 50 V or 60 V . What will be the current if the plate voltage is 70 V ?

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Two identical triode tubes are connected in parallel, as shown in the figure. The anodes are joined together, the grids are joined together, and the cathodes are joined together. A

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When 60 volts are applied across a diode tube, a plate current of 10 mA is obtained. Assuming that the Langmuir–Child equation i_p V_p^ 3/2 is valid, determine the dynamic resistan

Concepts Of Physics MCQ Edition [Volume 2] Solution View → 29

For a 6F6 triode tube, the plate current, plate voltage, and grid voltage are related by i_p = 41(V_p + 7 V_g)^ 1.41 , where V_p and V_g are in volts and i_p is in microamperes. If

Concepts Of Physics MCQ Edition [Volume 2] Solution View → 30

For a 6F6 triode tube, the plate current, plate voltage, and grid voltage are related by i_p = 41(V_p + 7 V_g)^ 1.41 , where V_p and V_g are in volts and i_p is in microamperes. If

Concepts Of Physics MCQ Edition [Volume 2] Solution View → 31

Cathode rays are travelling through a discharge tube. Inside the tube, there exists

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When a diode exhibits saturated current, its dynamic plate resistance is

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The anode of a thermionic diode is wired to the negative terminal of a battery, while the cathode is wired to the positive terminal.

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Suppose i₀ represents the thermionic current emitted from a metal surface at an absolute temperature T₀ . If the temperature is gradually increased and the thermionic current is re

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Cathode rays consist of a stream of

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A 50 Hz AC source, a diode, and a resistor are wired together in series. What is the number of current pulses per second flowing through the resistor?

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In a triode valve, the plate current reaches its maximum value when the grid potential is

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A triode operates within the linear region of its characteristics. If the plate voltage is subjected to a slight increase, the dynamic plate resistance will

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For a triode operating in the linear region, the amplification factor is strongly dependent on

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Within a discharge tube, electric conduction occurs due to the motion of

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The saturation current in a triode valve can be altered by varying

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Identify the correct statements from the following:

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Which of the following statements hold true for a cathode ray?

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As a result of the space charge in a diode valve,

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If the plate current in a diode is found to be zero, it is possible that

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The plate current in a triode valve is observed to be zero, even though its filament temperature is high. This situation is possible when

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