Description : The threshold frequency is the frequency below which - (1) photo current is constant (2) photo current increases with voltage (3) photo current decreases with volt (4) photo electric emission is not possible
Last Answer : (4) photo electric emission is not possible
Description : The threshold frequency is the frequency below which – (1) photo current increases with voltage (2) photo current decreases with voltage (3) photo electric emission is not possible (4) photo current is constant
Last Answer : (3) photo electric emission is not possible Explanation: The photoelectric effect is the emission of electrons by substances, especially metals, when light falls on their surfaces. The photoelectric ... gain sufficient energy to overcome the electrostatic barrier of the work function of the metal.
Description : The threshold frequency is the frequency below which : (1) photo current increases with voltage (2) photo current decreases with voltage (3) photo electric emission is not possible (4) photo current is constant
Last Answer : photo electric emission is not possible
Description : The reaction rate almost gets doubled for 10°C rise in temperature. This is due to the fact that the (A) Increased temperature reduces the activation energy (B) Fraction of molecules having threshold energy increases (C) Collision frequency increases (D) Value of threshold energy decreases
Last Answer : (B) Fraction of molecules having threshold energy increases
Description : The minimum frequency required to eject electrons from a metallic surface is called a) Critical frequency b) Peak value of frequency c) Threshold frequency d)Photo frequency
Last Answer : c) Threshold frequency
Description : The minimum energy required to eject an electron from a metal surface is called a) Intensity b) Threshold frequency c) Work function d) Photo energy
Last Answer : c) Work function
Description : A sine wave voltage is applied across an inductor. When the frequency of the voltage is decreased, the current decreases.
Last Answer : The question seems to be wrong. Increase in frequency would actually decrease the current through the Inductor. This happens because inductive reactance Xl is directly proportional to frequency. And if frequency increases the value of Xl would ... vice versa. Xl= 2*pi*f*L I=E/Z Z=sqrt(R^2+Xl^2)
Description : When the voltage remains constant, and the resistance increases in a series circuit, current flow _____________. A. decreases B. remains the same C. increases D. increases by the square
Last Answer : Answer: A
Description : When the voltage remains constant and the resistance is increased in a series circuit, the flow of current _____________. A. increases by the square of the original value B. increases C. remains the same D. decreases
Last Answer : Answer: D
Description : The emission of number of photo electrons depends upon a) The colour of the body b) The frequency of incident light c) The intensity of light d) All of the above
Last Answer : c) The intensity of light
Description : Which of the following is not a source of ozone emission in the atmosphere? (A) Refrigerators (B) Xerox machines (C) Dermatological photo-therapy equipments (D) High voltage electrical equipments
Last Answer : (A) Refrigerators
Description : The process, whereby electrons gain sufficient energy to be released from the surface of a thin, heated metal plate, is known as _____________. A. photo electric emission B. secondary emission C. thermionic emission D. regressive emission
Last Answer : Answer: C
Description : The threshold frequency is the frequency below which–
Last Answer : Photoelectric emission is not possible
Description : With increase in temperature, the rate constant obeying Arrhenius equation (A) Increases (B) Decreases (C) Decreases exponentially (D) Can either increase or decrease; depends on the frequency factor
Last Answer : (C) Decreases exponentially
Description : The magnitude of saturation photo electric current depends upon (a) Frequency (b) Intensity (c) Work function (d) Stopping potential
Last Answer : Ans:(b)
Description : For V/F control, when frequency is increased in transformer a) Core loss component current increases, Magnetizing component current decreases b) Core loss component current increases, ... component current decreases d) Core loss component current decreases, Magnetizing component current increases
Last Answer : Ans: Core loss component current decreases, Magnetizing component current decreases
Description : Which of the following statements is true concerning a stepdown transformer in an operating AC power circuit? A. Voltage and current will both be increased. B. Voltage and current will both be decreased C. Voltage decreases as current increases. D. Voltage increases as current decreases.
Description : According to Ohm’s law, what happens to circuit current if the applied voltage (a) increases, (b) decreases?
Last Answer : (a) Current increases (b) Current decreases
Description : What is threshold frequency?
Last Answer : Ans –The minimum frequency required to eject out electron from an atom.
Description : By accelerating the magnet inside the coil, the current in it A. increases B. decreases C. remains constant D. reverses
Last Answer : increases
Description : By increasing the current, the drift velocity A. decreases B. increases C. remains constant D. becomes zero
Last Answer : remains constant
Description : If there is a reduction in the normally supplied frequency to a 120/240 volt, threephase AC current motor from 60 hertz to 55 hertz, the motor would _____________. A. run at a slower speed B. operate at a lower current C. overheat D. trip off the line
Description : When iron rusts, its weight - (1) decreases (2) increases (3) Constant (4) None
Last Answer : (2) increases Explanation: Iron rust when they come into contact with water and oxygen. They rust faster in salty water or acid rain.
Description : A common-emitter circuit has an input voltage of 0.1 volt, an output voltage of 2.0 volts, an input current of 0.5 milliamps, and an output current of 10 milliamps. What is the power gain? A. 20 B. 40 C. 400 D. 4000
Description : A battery is connected to a circuit containing three resistors in parallel. The values of the three resistors are 2 ohms, 3 ohms, and 6 ohms. What is the voltage of the battery if the total circuit current is 12 amps? A. 2 volts B. 6 volts C. 12 volts D. 24 volt
Description : A device which can be used to check the calibration of a circuit breaker is a _________________. A. 500 volt megohmmeter B. portable low voltage high current testing unit C. standard digital multimeter D. clamp-on voltmeter
Last Answer : Answer: B
Description : To properly use a hook-on-type volt/ammeter to check current flow, you must FIRST _____________. A. de-energize the circuit to allow connection of the instrument in series B. hook the jaws ... test leads to the appropriate terminals D. short the test leads and calibrate the instrument to zero
Description : An LED is operated on a 12 volt automobile circuit. The voltage drop across the LED is 2 volts and the current must be limited to 50 milliamps to prevent its overheating and destruction. What size resistor must be used? w) 60 ohms x) 100 ohms y) 120 ohms z) 200 ohms
Last Answer : ANSWER: Z -- 200 OHMS
Description : Electric current is the flow of electrons through a conductor. The rate of this flow is measured as ___________. A. volts/watt B. amperes/centimetre C. coulombs/second D. ohms/volt
Description : An electric clothes dryer is connected to a 100-volt source. How much current does it use if it requires 2,000 watts of electric power?
Last Answer : 20 Amphere
Description : Electric current may be expressed in which one of the following units? w) coulombs/volt x) joules/coulomb y) coulombs/second z) ohms/second
Last Answer : ANSWER: Y -- COULOMBS/SECOND
Description : Describe the process of photo emission. State the application of photo emission in electronic components
Last Answer : Process of Photoemission:when light of appropriate frequency and intensity is incident upon a surface of certain materials,the energy of light is given to electrons to leave the surface of metal ... photo tubes are used in door openers,counters, position and temperature control and colour analysis
Description : 25 A step up transformer increases A. voltage B. current C. power D. frequency
Last Answer : A. Voltage
Description : 16.step-up transformer increases A. voltage B. current C. power D. frequency
Description : Decreasing the frequency in a capacitive circuit while maintaining a constant circuit voltage, will result in a/an _____________. A. increase in apparent power B. decrease in circuit current C. decrease in capacitive reactance D. decrease in total impedance
Description : Load regulation is a measure of a power supplies ability keep a constant output under conditions of changing A) Line voltage B) Current demand C) Temperature D) Oscillator frequency.
Last Answer : A) Line voltage
Description : In a load flow analysis of a power system, the load connected at a bus is represented as a) Constant current drawn from the bus b) Constant impedance connected at the bus c) Voltage and frequency dependent sources at the boss d) Constant real and reactive power drawn from the bus
Last Answer : d) Constant real and reactive power drawn from the bus
Description : In the ________ algorithm of TCP, the size of the congestion window increases exponentially until it reaches a threshold A. slow-start B. congestion avoidance C. congestion detection D. none of the above
Last Answer : A. slow-start
Description : The following is true about actions of ethylalcohol: A. It exerts anticonvulsant action followed by lowering of seizure threshold B. It lowers pain threshold C. It increases confidence and reduces number of errors D. It increases heat production and helps to keep warm in cold weather
Last Answer : A. It exerts anticonvulsant action followed by lowering of seizure threshold
Description : Decision to stop testing should be based upon A. Successful use of specific test case design methodologies B. A percentage of coverage for each coverage category C. Rate of error detection falls below a specified threshold D. All of the above
Last Answer : D. All of the above
Description : The threshold effect in demodulators is a) The rapid fall of output SNR when the input SNR falls below a particular value b) Exhibited by all the demodulators when the input SNR is low c) Exhibited by all AM suppressed carrier coherent demodulators d) Exhibited by correlation receivers
Last Answer : The threshold effect in demodulators is The rapid fall of output SNR when the input SNR falls below a particular value
Description : In human relations the irritation threshold is the A. action that causes an annoyance. B. frequency of the annoying behavior. C. point at which a person notices something and becomes annoyed. D. lengt?
Last Answer : Need answer
Description : Compared with myelinated nerve fibres, non-myelinated nerve fibres : a. have a higher threshold for stimulation b. have a longer refractory period c. transmit impulses at a lower frequency d. all above
Last Answer : all above
Description : Pick up the correct statement from the following: (A) The minimum frequency of light for which no electrons are emitted, is called threshold frequency (B) Polarising angle of glass is 57.5° (C) At the polarising angle, the reflected and refracted rays are orthogonal (D) All the above
Last Answer : Answer: Option D
Description : When a certain beam of light falls upon a metal surface, it ejects photoelectrons from it. The number of photoelectrons ejected per second by the beam of light depends upon one of the following. Is it ... the work function of the metal y) the frequency of the beam z) the intensity of the beam
Last Answer : ANSWER: Z -- THE INTENSITY OF THE BEAM
Description : Define : (i)Threshold frequency (ii)Work function
Last Answer : Threshold frequency: The minimum frequency of incident radiation at which emission of photoelectrons starts is called Threshold frequency. Work function: The amount of energy required to detach the electron from metal surface is called work function.
Description : Define Threshold voltage in CMOS?
Last Answer : The Threshold voltage, VT for a MOS transistor can be defined as the voltage applied between the gate and the source of the MOS transistor below which the drain to source current, IDS effectively drops to zero.
Description : Assume that the n-channel MOSFET shown in figure is ideal and that its threshold voltage is +1 .0 V. The voltage Vab between nodes a and b is A)5V B)2V C)1V D)0V
Last Answer : Assume that the n-channel MOSFET shown in figure is ideal and that its threshold voltage is +1 .0 V. The voltage Vab between nodes a and b is 0V
Description : Threshold voltage for PMOS is generally (A) Negative (B) Positive (C) Zero (D) None of the above
Last Answer : Threshold voltage for PMOS is generally Negative