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Assertion (A): Typical value of thermal resistance from source to sink of an SCR is about 0.3° C/W Reason (R): Heat sinks of thyristors are generally made of aluminium. | |
A. | Both A and R are correct and R is correct explanation of A [Wrong Answer] |
B. | Both A and R correct but R is not correct explanation of A [Correct Answer] |
C. | A is correct but R is wrong [Wrong Answer] |
D. | A is wrong but R is correct [Wrong Answer] |
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Explanation:-
Answer : B Discuss it below : !! OOPS Login [Click here] is required to post your answer/result |
Also Read Similar Questions Below :
⇒ If temperature is increased, the temperature coefficient of a metal
increases
decreases
may increase or decrease
remains constant
⇒ If E is energy level of electron and E_{F} is Fermi level, then
all quantum states with E less than E_{F} will be occupied at T = 0
all quantum states with E less than E_{F} will be empty at T = 0
some quantum states with E less than E_{F} will be occupied at T = 0
none of the above
⇒ Acoustic strain gauges
have good linearity of measurement
do not have long term stability
have a large range of measurement
have an accuracy range of 0.1-1% depending on environment
⇒ A VF display operates on the principle of a vacuum diode.
TRUE
FALSE
⇒
Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
A is wrong but R is correct
⇒ The logic circuit in the given figure realizes the func
(A + B + C) (D E)
(A + B + C) (D E)
(A + B + C) (D E)
(A + B + C) (D E)
⇒ In the balanced bridge shown in figure. X should
a self inductance having resistance
a capacitance
a non-inductive resistance
an inductance and capacitance in parallel
⇒ In a second order system, peak overshoot is independent of
damping factor
natural frequency
both damping factor and natural frequency
neither damping factor nor natural frequency
⇒ Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is
0.25 mH
0.5 mH
0.707 mH
1 mH
⇒ Unit of e is __________ .
coulomb/newton-metre
coulomb^{2}/newton-metre
Farad/metre
Farad^{2}/metre
⇒ An op-amp is fed from a signal source through resistance R_{1}. If it is to work as sign changer, the feedback resistance R_{f} should be
equal to R_{1}
twice R_{1}
half R_{1}
either (b) or (c)
⇒ A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if
load torque is constant
load torque increases with increase in speed
load torque decreases with increase in speed
either (a) or (b)
⇒
A-1, B-2, C-3
A-2, B-4, C-5
A-1, B-3, C-4
A-2, B-3, C-5
⇒ Two sinusoidal voltage sources v_{1} = 50 sin (100t) and v_{1} = 50 sin (100t + p) are connected in parallel and fed an inductance X_{L} = 2Ω. The cuirent through X_{L} is
25 A
about 17.5 A
zero
50 A
⇒ A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is
6 mV
12 mV
24 mV
3 mV
⇒ Which of the following is true for RC impedance?
The lowest critical frequency is a pole
The lowest critical frequency is zero
The lowest critical frequency may be pole or zero
The lowest critical frequency is a pole but cannot be at s = 0
⇒ In a positive-edge-triggered JK flip-flop, a low J and a low K produce __________ state. A high __________ on the rising edge of the clock.
inactive, reset
active, reset
active, toggle
inactive, toggle
⇒ Some typical examples of macroscopic quantities are
conductivity
µ_{r}
dielectric constant
all of the above
⇒ In band III of TV, distant reception (beyond line of sight range) is possible due to
tropospheric bending by refraction
reflection of waves
ionospheric scattering
none of the above
⇒ In a crystal oscillator of the Colpitt's oscillator type, the crystal is put is place of the
resistor R_{1}
condenser C_{2}
condenser C_{1}
inductor L
⇒ Wired AND connection can be used in TTL with totem pole output.
TRUE
FALSE
⇒ The primary colours are
blue and green
blue and red
red and green
blue, red and green
⇒ A dc chopper V = 500 V feeds an electric fraction dc series motor. The chopping frequency is 400 Hz. The series inductance required to limit the maximum current swing to 10 A is
20 mH
about 31 mH
about 51 mH
about 92 mH
⇒ A satellite that simply reflect back the signals from one region of the earth to the other region is known as
orbiting satellite
geostationary satellite
active satellite
passive satellite
⇒ In a bipolar transistor
recombination in base regions of both n-p-n and p-n-p transistor is low
recombination in base regions of both n-p-n and p-n-p transistors is high
recombination in base region of n-p-n transistor is low but that in p-n-p transistor is high
recombination in base region of p-n-p transistor is low but that in n-p-n transistor is high
⇒ If the characteristic equation is (λ + 1) (λ + 2) (λ + 3) = 0, the eigen values are
-1, -2, -3
1, 2, 3
0, 1, 2
0, 2, 3
⇒ Binary 101010 is equivalent to decimal number
24
42
44
64
⇒ A system has 12 poles or 2 zeros. Its high frequency asymptote in its magnitude plot has slope of
-200 dB/decade
-240 dB/decade
-280 dB/decade
-320 dB/decade
⇒ The inverse of given Laplace transfor
sin t
cos t
e^{t}
e^{2t}
⇒ If the bandwidth is increased by 2, the γ_{FM} γ_{AM} (where γ is the ratio of SNR of output to SNR at input, FM is frequency modulation and AM is amplitude modulation) is increased by a factor of
2
3
4
6
⇒ If temperature is increased, the temperature coefficient of a metal
increases
decreases
may increase or decrease
remains constant
⇒ If E is energy level of electron and E_{F} is Fermi level, then
all quantum states with E less than E_{F} will be occupied at T = 0
all quantum states with E less than E_{F} will be empty at T = 0
some quantum states with E less than E_{F} will be occupied at T = 0
none of the above
⇒ Acoustic strain gauges
have good linearity of measurement
do not have long term stability
have a large range of measurement
have an accuracy range of 0.1-1% depending on environment
⇒ A VF display operates on the principle of a vacuum diode.
TRUE
FALSE
⇒
Assertion (A): Impatt diode can be used in both amplifiers and oscillators.
Reason (R): Impatt diode has a low resistance.
Both A and R are correct and R is correct explanation of A
Both A and R are correct but R is not correct explanation of A
A is correct but R is wrong
A is wrong but R is correct
⇒ The logic circuit in the given figure realizes the func
(A + B + C) (D E)
(A + B + C) (D E)
(A + B + C) (D E)
(A + B + C) (D E)
⇒ In the balanced bridge shown in figure. X should
a self inductance having resistance
a capacitance
a non-inductive resistance
an inductance and capacitance in parallel
⇒ In a second order system, peak overshoot is independent of
damping factor
natural frequency
both damping factor and natural frequency
neither damping factor nor natural frequency
⇒ Two similar coils have self inductance of 1 mH each. Coefficient of coupling is 0.5. The mutual inductance M is
0.25 mH
0.5 mH
0.707 mH
1 mH
⇒ Unit of e is __________ .
coulomb/newton-metre
coulomb^{2}/newton-metre
Farad/metre
Farad^{2}/metre
⇒ An op-amp is fed from a signal source through resistance R_{1}. If it is to work as sign changer, the feedback resistance R_{f} should be
equal to R_{1}
twice R_{1}
half R_{1}
either (b) or (c)
⇒ A 3 phase induction motor is fed by a 3 phase ac regulator to change the stator voltage. The variation in speed will be more if
load torque is constant
load torque increases with increase in speed
load torque decreases with increase in speed
either (a) or (b)
⇒
Match the following:
List I | List II | ||
---|---|---|---|
A. | Fourier transform of a Gaussian function | 1. | Gaussian function |
B. | Convolution of a rectangular pulse with itself | 2. | Rectangular pulse |
C. | Current through inductor for step input voltage | 3. | Triangular pulse |
4. | Ramp function | ||
5. | Zero |
A-1, B-2, C-3
A-2, B-4, C-5
A-1, B-3, C-4
A-2, B-3, C-5
⇒ Two sinusoidal voltage sources v_{1} = 50 sin (100t) and v_{1} = 50 sin (100t + p) are connected in parallel and fed an inductance X_{L} = 2Ω. The cuirent through X_{L} is
25 A
about 17.5 A
zero
50 A
⇒ A sinusoidal signal is measured by CRO. The scale is set at 4 mV/cm. If vertical distance between positive and negative peaks is 6 cm, the peak value of ac signal is
6 mV
12 mV
24 mV
3 mV
⇒ Which of the following is true for RC impedance?
The lowest critical frequency is a pole
The lowest critical frequency is zero
The lowest critical frequency may be pole or zero
The lowest critical frequency is a pole but cannot be at s = 0
⇒ In a positive-edge-triggered JK flip-flop, a low J and a low K produce __________ state. A high __________ on the rising edge of the clock.
inactive, reset
active, reset
active, toggle
inactive, toggle
⇒ Some typical examples of macroscopic quantities are
conductivity
µ_{r}
dielectric constant
all of the above
⇒ In band III of TV, distant reception (beyond line of sight range) is possible due to
tropospheric bending by refraction
reflection of waves
ionospheric scattering
none of the above
⇒ In a crystal oscillator of the Colpitt's oscillator type, the crystal is put is place of the
resistor R_{1}
condenser C_{2}
condenser C_{1}
inductor L
⇒ Wired AND connection can be used in TTL with totem pole output.
TRUE
FALSE
⇒ The primary colours are
blue and green
blue and red
red and green
blue, red and green
⇒ A dc chopper V = 500 V feeds an electric fraction dc series motor. The chopping frequency is 400 Hz. The series inductance required to limit the maximum current swing to 10 A is
20 mH
about 31 mH
about 51 mH
about 92 mH
⇒ A satellite that simply reflect back the signals from one region of the earth to the other region is known as
orbiting satellite
geostationary satellite
active satellite
passive satellite
⇒ In a bipolar transistor
recombination in base regions of both n-p-n and p-n-p transistor is low
recombination in base regions of both n-p-n and p-n-p transistors is high
recombination in base region of n-p-n transistor is low but that in p-n-p transistor is high
recombination in base region of p-n-p transistor is low but that in n-p-n transistor is high
⇒ If the characteristic equation is (λ + 1) (λ + 2) (λ + 3) = 0, the eigen values are
-1, -2, -3
1, 2, 3
0, 1, 2
0, 2, 3
⇒ Binary 101010 is equivalent to decimal number
24
42
44
64
⇒ A system has 12 poles or 2 zeros. Its high frequency asymptote in its magnitude plot has slope of
-200 dB/decade
-240 dB/decade
-280 dB/decade
-320 dB/decade
⇒ The inverse of given Laplace transfor
sin t
cos t
e^{t}
e^{2t}
⇒ If the bandwidth is increased by 2, the γ_{FM} γ_{AM} (where γ is the ratio of SNR of output to SNR at input, FM is frequency modulation and AM is amplitude modulation) is increased by a factor of
2
3
4
6