Physics-
General
Easy
Question
An oxide coated filament is useful in vacuum tubes because essentially
- It has high melting point
- It can withstand high temperatures
- It has good machanical strength
- It can emit electrons at relatively lower temperatures
The correct answer is: It can emit electrons at relatively lower temperatures
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In an electron gun the control grid is given a negative potential relative to cathode in order to
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In Millikan's experiment for the determination of the charge on the electron, the reason for using the oil is
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If A and B are identical bulbs which bulbs glows brighter
If A and B are identical bulbs which bulbs glows brighter
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Following figure shows an ac generator connected to a "block box" through a pair of terminals. The box contains possible R, L, C or their combination, whose elements and arrangements are not known to us. Measurements outside the box reveals that
e = 75 sin (sin 
t) volt, i = 1.5 sin ( t + 45o) amp then, the wrong statement is
Following figure shows an ac generator connected to a "block box" through a pair of terminals. The box contains possible R, L, C or their combination, whose elements and arrangements are not known to us. Measurements outside the box reveals that
e = 75 sin (sin t) volt, i = 1.5 sin ( t + 45o) amp then, the wrong statement is
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Which of the following plots may represent the reactance of a series LC combination
Which of the following plots may represent the reactance of a series LC combination
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The graphs given below depict the dependence of two reactive impedances X1 and X2 on the frequency of the alternating e.m.f. applied individually to them. We can then say that
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The resonance point in 
and 
curves is
The resonance point in and curves is
Physics-General
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The vector diagram of current and voltage for a circuit is as shown. The components of the circuit will be
The vector diagram of current and voltage for a circuit is as shown. The components of the circuit will be
Physics-General
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The voltage across a pure inductor is represented by the following diagram. Which one of the following diagrams will represent the current
The voltage across a pure inductor is represented by the following diagram. Which one of the following diagrams will represent the current
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Two sinusoidal voltages of the same frequency are shown in the diagram. What is the frequency, and the phase relationship between the voltages
Frequency in Hz Phase lead of N over M in radians</span
Two sinusoidal voltages of the same frequency are shown in the diagram. What is the frequency, and the phase relationship between the voltages
Frequency in Hz Phase lead of N over M in radians</span
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When an ac source of e.m.f. 
is connected across a circuit, the phase difference between the e.m.f. e and the current i in the circuit is observed to be 
, as shown in the diagram. If the circuit consists possibly only of RC or LC in series, find the relationship between the two elements [IIT-JEE (Screening) 2003]
When an ac source of e.m.f. is connected across a circuit, the phase difference between the e.m.f. e and the current i in the circuit is observed to be , as shown in the diagram. If the circuit consists possibly only of RC or LC in series, find the relationship between the two elements [IIT-JEE (Screening) 2003]
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The current 'i' in an inductance coil varies with time 't' according to following graph
Which one of the following plots shows the variations of voltage in the coil
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Which one of the following plots shows the variations of voltage in the coil
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The output current versus time curve of a rectifier is shown in the figure. The average value of output current in this case is
The output current versus time curve of a rectifier is shown in the figure. The average value of output current in this case is
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A constant voltage at different frequencies is applied across a capacitance C as shown in the figure. Which of the following graphs
Correctly depicts the variation of current with frequency ?
A constant voltage at different frequencies is applied across a capacitance C as shown in the figure. Which of the following graphs
Correctly depicts the variation of current with frequency ?
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The r.m.s. voltage of the wave form shown is
The r.m.s. voltage of the wave form shown is
Physics-General
