MCQOPTIONS
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MCQOPTIONS
This section includes 1800 Mcqs, each offering curated multiple-choice questions to sharpen your Electronics & Communication Engineering knowledge and support exam preparation. Choose a topic below to get started.
| 901. |
Calculate i(t) for t ‚â• 0, assuming the switch has been in position A for a long time at t = 0, the switch is moved to position B. |
| A. | 1 + e-5 x 103t |
| B. | e-5 x 103t |
| C. | 1.11 e-5 x 103t |
| D. | 1.11 (1 - e-5 x 103t) |
| Answer» D. 1.11 (1 - e-5 x 103t) | |
| 902. |
A constant k band pass filter has a pass band from 100 to 400 Hz. The resonant frequency of series and shunt arms is |
| A. | 3000 Hz |
| B. | 2500 Hz |
| C. | 2000 Hz |
| D. | 1500 Hz |
| Answer» D. 1500 Hz | |
| 903. |
Consider the following statements : Tellegen's theorem is applicable to any lumped networks.The reciprocity theorem is applicable to linear bilateral networks.Thevenin's theorem is applicable to two- terminal linear active networks.Norton's theorem is applicable to two-terminal linear active networks. Which of these statement are correct? |
| A. | 1, 2, and 3 |
| B. | 1, 2 and 4 |
| C. | 1, 2, 3 and 4 |
| D. | 3 and 4 |
| Answer» D. 3 and 4 | |
| 904. |
The graph of a network has 6 branches with 3 tree branches. The minimum number of equations required for solution of network is |
| A. | 2 |
| B. | 3 |
| C. | 4 |
| D. | 5 |
| Answer» C. 4 | |
| 905. |
In the voltage equation v = 500 sin (1000t) V, the rms value of voltage is |
| A. | 500 V |
| B. | 5002 V |
| C. | |
| Answer» D. | |
| 906. |
If e = 110 sin (ωt + p/3) and i = 5 sin (ωt - p/3), the impedance of the circuit is |
| A. | 30.8 Ω |
| B. | 11 Ω |
| C. | v1 = Vm1 sin θ and v2 = Vm2 cos θ |
| D. | v1 = Vm1 sin ωt and v2 = Vm2 sin (ωt - θ) |
| Answer» B. 11 Œ© | |
| 907. |
Three inductors each 30 mH are connected in delta. The value of inductance or each arm of equivalent star is |
| A. | 10 mH |
| B. | 15 mH |
| C. | 30 mH |
| D. | 90 mH |
| Answer» B. 15 mH | |
| 908. |
For a transfer function H(s) = P(s)/Q(s), where P(s) and Q(s) are polynomials in s |
| A. | the degrees of P(s) is always greater than degree of Q(s) |
| B. | the degree of P(s) and Q(s) are equal |
| C. | the degree of P(s) is independent of degree of Q(s) |
| D. | the maximum difference in degrees of P(s) and Q(s) is 1 |
| Answer» D. the maximum difference in degrees of P(s) and Q(s) is 1 | |
| 909. |
The frame of an electric motor is earthed through three earthing plates resistances 30 Ω, 20 Ω and 10 Ω respectively. During fault the energy dissipated by three plates are W1, W2 and W3. Then |
| A. | W1 > W2 > W3 |
| B. | W1 < W2 < W3 |
| C. | W1 = W2 = W3 |
| D. | W1 + W3 < W2 |
| Answer» C. W1 = W2 = W3 | |
| 910. |
In a circuit containing a complex impedance, maximum power transfer takes place when load is |
| A. | pure resistance |
| B. | equal to the complex impedance |
| C. | conjugate complex of the circuit impedance |
| D. | none of the above |
| Answer» D. none of the above | |
| 911. |
Tesla is unit of |
| A. | Φ |
| B. | B |
| C. | H |
| D. | MMF |
| Answer» C. H | |
| 912. |
At resonance, the parallel circuit constituted by an iron-cored coil and a capacitor behaves like |
| A. | open circuit |
| B. | short circuit |
| C. | pure resistor of value R |
| D. | pure resistor of value much higher than R |
| Answer» E. | |
| 913. |
P(s) = s4 + s3 + 2s2 + 4s + 3Q(s) = s4 + 2s3 + s Which one of the following statements in correct for above P(s) and Q(s) polynomials? |
| A. | Both P(s) and Q(s) are Hurwitz |
| B. | Both P(s) and Q(s) are non-Hurwitz |
| C. | P(s) is Hurwitz but Q(s) is non-Hurwitz |
| D. | P(s) is non-Hurwitz but Q(s) is Hurwitz |
| Answer» D. P(s) is non-Hurwitz but Q(s) is Hurwitz | |
| 914. |
In a lead acid cell, the positive plate has spongy lead. |
| A. | 1 |
| B. | |
| C. | 10 volt |
| D. | 2 volt |
| Answer» C. 10 volt | |
| 915. |
The current source in figure, can be replaced by |
| A. | a voltage source of 20 V in series with 5 ohm resistance |
| B. | a voltage source of 16 V in series with 4 ohm resistance |
| C. | a voltage source of 20 V in series with 4 Ω resistance |
| D. | a voltage source of 16 V in series with 5 Ω resistance |
| Answer» C. a voltage source of 20 V in series with 4 Œ© resistance | |
| 916. |
When a lead acid battery is fully charged the colours of its positive and negative plates are |
| A. | grey and dark brown |
| B. | dark grey and brown |
| C. | grey and brown |
| D. | dark brown and grey |
| Answer» E. | |
| 917. |
For circuit in figure, which combination of VTH and RTH represents the circuit as seen from ab? |
| A. | 1 V, 10 Ω |
| B. | 1 V, 1000 Ω |
| C. | 1 mV, 1000 Ω |
| D. | 1 mV, 10 Ω |
| Answer» B. 1 V, 1000 Œ© | |
| 918. |
Two capacitors each of capacitance C and breakdown voltage V are joined in series. The capacitance and breakdown voltage of the combination is |
| A. | 0.5 C and 2 V |
| B. | 0.5 C and 0.5 V |
| C. | C and V |
| D. | 2 C and 2 V |
| Answer» B. 0.5 C and 0.5 V | |
| 919. |
Assertion (A): In a series resonant circuit current is maximum at resonance.Reason (R): The inductive and capacitive reactances are equal. |
| A. | Both A and R are true and R is correct explanation of A |
| B. | Both A and R are true and R is not the correct explanation of A |
| C. | A is true but R is false |
| D. | A is false but R is true |
| Answer» B. Both A and R are true and R is not the correct explanation of A | |
| 920. |
When a lead acid cell is in fully charged condition the specific gravity of electrolyte is about 1.22. |
| A. | 1 |
| B. | |
| C. | a capacitor |
| D. | a resistor |
| Answer» B. | |
| 921. |
In a tungsten filament lamp |
| A. | the current at the instant of switching is less than operating current |
| B. | the current at the instant of switching is more than operating current |
| C. | the current at the instant of switching is equal to operating current |
| D. | the current at the instant of switching may be less than or equal to operating current |
| Answer» E. | |
| 922. |
In a driving point function, the degrees of numerator and denominator polynomials in s may differ by either zero or one only. |
| A. | 1 |
| B. | |
| C. | 1 |
| D. | |
| Answer» B. | |
| 923. |
A 1 μF capacitor is connected to 12 V battery. The energy stored in the capacitor is |
| A. | 12 x 10-6 J |
| B. | 24 x 10-6 J |
| C. | 48 x 10-6 J |
| D. | 72 x 10-6 J |
| Answer» E. | |
| 924. |
If Va = 10 ∠0, Vb = 10 ∠ -120° and Vc = 10 ∠ -240°, then Va2 and Va0 are |
| A. | 10 and 0 respectively |
| B. | 0 and 10 respectively |
| C. | 0 and 0 |
| D. | 10 and 10 |
| Answer» B. 0 and 10 respectively | |
| 925. |
The value of current at resonance in series R-L-C circuit is affected by the value of |
| A. | C |
| B. | L |
| C. | R |
| D. | all of the above |
| Answer» D. all of the above | |
| 926. |
Consider the following statements Current through inductor cannot change abruptly.Voltage across capacitor cannot change abruptly.Initial value of f(t) is sF (s).Final value of f(t) is sF (s). Of the above statements |
| A. | 3 and 4 are correct |
| B. | 1 and 4 are correct |
| C. | 1 and 2 are correct |
| D. | 2 and 3 are correct |
| Answer» D. 2 and 3 are correct | |
| 927. |
In a series RLC circuit excited by e = Em sin ωt is seen that LC < 1/ω2. Then |
| A. | I lags E |
| B. | I leads E |
| C. | I leads E are in phase |
| D. | voltage across L and C are equal |
| Answer» C. I leads E are in phase | |
| 928. |
If a function Z(s) has a pole at infinity, then |
| A. | the degrees of numerator and denominator are equal |
| B. | the degree of numerator is one higher than that of denominator |
| C. | the degree of denominator is one higher than that of numerator |
| D. | the difference between the degrees of numerator and denominator is 0 or 1 |
| Answer» C. the degree of denominator is one higher than that of numerator | |
| 929. |
In an R-L-C series circuit, R = 2/L/C . If R is doubled |
| A. | the response will become underdamped |
| B. | the response will become overdamped |
| C. | the response will be critically damped |
| D. | the response may be under damped or overdamped |
| Answer» C. the response will be critically damped | |
| 930. |
The resonance frequency is |
| A. | ωr = a |
| B. | ωr = b |
| C. | ωr = k |
| D. | ωr = ba |
| Answer» C. œâr = k | |
| 931. |
Which of the following is not a non-linear element? |
| A. | Diode |
| B. | Electric arc with unlike electrodes |
| C. | planar network |
| D. | planar and Non-planar both |
| Answer» C. planar network | |
| 932. |
Power factor of the following circuit will be unity |
| A. | inductance |
| B. | capacitance |
| C. | resistance |
| D. | both (a) and (b) |
| Answer» D. both (a) and (b) | |
| 933. |
For the wave shown in figure, the average and rms values are |
| A. | 50 A and 57.73 A |
| B. | 57.73 A and 50 A |
| C. | 25 A and 57.73 A |
| D. | 57.73 A and 70.7 A |
| Answer» B. 57.73 A and 50 A | |
| 934. |
In an R-L circuit excited by a battery of voltage E, the current and voltage across resistor are 1- e-t and 2(1 - e-t) respectively. If there were an initial current of 2 A in the inductance, the voltage across resistance would have been |
| A. | 1 - e-t |
| B. | 2 - 2e-t |
| C. | 2 + 2e-t |
| D. | 4 - 4e-t |
| Answer» D. 4 - 4e-t | |
| 935. |
At half power frequencies the current in R-L-C series circuit is __________ times current at resonance |
| A. | 43525 |
| B. | 43556 |
| C. | 43497 |
| D. | 43497 |
| Answer» D. 43497 | |
| 936. |
R, L and C are in parallel. The circuit is switched on to a constant current source I at t = 0. At t = ‚àû the current through inductance is I. |
| A. | 1 |
| B. | |
| C. | 0.5 A |
| D. | 1.0 A |
| Answer» B. | |
| 937. |
Figure shows a parallel resonant circuit having resonance frequency of 15 MHZ. At this frequency |
| A. | its impedance is minimum |
| B. | its impedance is maximum |
| C. | its impedance is infinite |
| D. | its impedance is zero |
| Answer» C. its impedance is infinite | |
| 938. |
In solid dielectrics the rate of deterioration doubles for every 10-12°C rise in temperature. |
| A. | 1 |
| B. | |
| C. | E/R |
| D. | E/LC |
| Answer» B. | |
| 939. |
In |
| A. | |
| B. | |
| Answer» C. | |
| 940. |
In a series RLC circuit, the current at resonance is I0 the total energy stored in the circuit at resonance is |
| A. | LI02 |
| B. | 2 LI02 |
| C. | 2 LI02 |
| D. | 0.5 LI2 |
| Answer» B. 2 LI02 | |
| 941. |
Three resistance of 15 Ω each are connected in delta. The resistance of equivalent star will have a value of |
| A. | 15 Ω |
| B. | 5 Ω |
| C. | 5/3 Ω |
| D. | 45 Ω |
| Answer» C. 5/3 Œ© | |
| 942. |
A constant k low pass T section filter has a characteristic impedance of 600 p at zero frequency. At f = fc the characteristic impedance is |
| A. | 600 Ω |
| B. | zero |
| C. | infinite |
| D. | more than 600 ohms |
| Answer» C. infinite | |
| 943. |
The temperature coefficient of copper is 0.00393 at 20° C. At 50° C the temperature coefficient is |
| A. | 0.0042 |
| B. | 0.0035 |
| C. | 0.0025 |
| D. | 0.0015 |
| Answer» C. 0.0025 | |
| 944. |
Paper capacitors are used in power supplies for filtering. |
| A. | 1 |
| B. | |
| C. | (t2* e-2t) U(t) |
| D. | (t* e2t) U(t) |
| Answer» B. | |
| 945. |
Evaluate the value of 2 [u (t - 1) - u (1 - 2t)] (u ( t + 1) + u (t)) at t = 3 sec. |
| A. | 0 |
| B. | 4 |
| C. | ‚àû |
| D. | 1 |
| Answer» C. ‚àû | |
| 946. |
A series RLC circuit has a resonant frequency of 2000 Hz. The maximum voltage across C is likely to occur at a frequency of about |
| A. | 2025 Hz |
| B. | 1975 Hz |
| C. | Both A and R are true and R is correct explanation of A |
| D. | Both A and R are true and R is not the correct explanation of A |
| Answer» D. Both A and R are true and R is not the correct explanation of A | |
| 947. |
The transfer function is for |
| A. | low pass filter |
| B. | notch filter |
| C. | high pass filter |
| D. | band pass filter |
| Answer» B. notch filter | |
| 948. |
If each branch of a Delta circuit has impedance 3 Z then each branch of the equivalent Y circuit has impedance. |
| A. | Z/3 |
| B. | 3 Z |
| C. | 3/3 Z |
| D. | Z/3 |
| Answer» B. 3 Z | |
| 949. |
For a reactance function H(s) |
| A. | Re [H(jω)] is positive for ω ≥ 0 |
| B. | Re [H(jω)] is zero for ω ≥ 0 |
| C. | Re [H(jω)] is positive or zero for ω ≥ 0 |
| D. | Re [H(jω)] is zero or negative for ω ≥ 0 |
| Answer» C. Re [H(jœâ)] is positive or zero for œâ ‚â• 0 | |
| 950. |
The ABCD parameters of ideal n : 1 transformer shown in the figure are . The value of X will be |
| A. | n |
| B. | 1/n |
| C. | n2 |
| D. | 1/n2 |
| Answer» C. n2 | |