

MCQOPTIONS
Saved Bookmarks
This section includes 113 Mcqs, each offering curated multiple-choice questions to sharpen your Concrete Technology knowledge and support exam preparation. Choose a topic below to get started.
1. |
The loss in weight should not exceed ________ % when tested with Na2SO4 and ________ % with MgSO4 solution. |
A. | 12, 18 |
B. | 18, 12 |
C. | 10, 15 |
D. | 15, 10 |
Answer» B. 18, 12 | |
2. |
The mineral oil if present in mixing for concrete ______________ |
A. | Improves strength |
B. | Reduces strength |
C. | Gives more slump |
D. | Gives a smooth surface |
Answer» B. Reduces strength | |
3. |
When sand is fully dry then it’s volume is _________ |
A. | Equal |
B. | Less |
C. | More |
D. | Can’t say |
Answer» B. Less | |
4. |
Loss on Ignition (L.O.I.) is the loss in weight of cement after being heated to ____________ |
A. | 1000°C |
B. | 100°C |
C. | 500°C |
D. | 1500°C |
Answer» B. 100°C | |
5. |
Find the Nyquist rate and Nyquist interval for the signal f(t) = -10 sin 40πt cos 300πt. |
A. | 40 Hz, 40 sec |
B. | 340 Hz, 340 sec |
C. | 300 Hz, 300 sec |
D. | 340 Hz, \(\frac{1}{340}\) sec |
Answer» E. | |
6. |
Determine the Nyquist rate of the signal x(t) = 1 + cos 2000πt + sin 4000πt. |
A. | 2000 Hz |
B. | 4000 Hz |
C. | 1 Hz |
D. | 6000 Hz |
Answer» C. 1 Hz | |
7. |
The sampling frequency of a signal is Fs = 2000 samples per second. Find its Nyquist interval. |
A. | 0.5 sec |
B. | 5 msec |
C. | 5 sec |
D. | 0.5 msec |
Answer» C. 5 sec | |
8. |
Find the Nyquist rate and Nyquist interval for the signal f(t) = rect(200t). |
A. | ∞ Hz, 0 sec |
B. | 0 Hz, ∞ sec |
C. | ∞ Hz, ∞ Hz |
D. | 0 Hz, 0 sec |
Answer» B. 0 Hz, ∞ sec | |
9. |
Find the Nyquist rate and Nyquist interval for the signal f(t) = 1 + sinc300πt. |
A. | 300 Hz, 3 msec |
B. | 300 Hz, 3.3 msec |
C. | 30 Hz, 3 msec |
D. | 3 Hz, 3 msec |
Answer» C. 30 Hz, 3 msec | |
10. |
Find the Nyquist rate and Nyquist interval for the signal f(t)=\(\frac{sin500πt}{πt}\). |
A. | 500 Hz, 2 sec |
B. | 500 Hz, 2 msec |
C. | 2 Hz, 500 sec |
D. | 2 Hz, 500 msec |
Answer» C. 2 Hz, 500 sec | |
11. |
Which of the following is the process of ‘aliasing’? |
A. | Peaks overlapping |
B. | Phase overlapping |
C. | Amplitude overlapping |
D. | Spectral overlapping |
Answer» E. | |
12. |
Find the Nyquist rate and Nyquist interval of sinc[200t]. |
A. | 200 Hz, \(\frac{1}{200}\) sec |
B. | 200 Hz, 200 sec |
C. | \(\frac{1}{200}\) Hz, 200 sec |
D. | 100 Hz, 100 sec |
Answer» B. 200 Hz, 200 sec | |
13. |
Find the Nyquist rate and Nyquist interval of Asinc[t]. |
A. | 2 Hz, 2 sec |
B. | 1 Hz, 1 sec |
C. | \(\frac{1}{2}\) Hz, 1 sec |
D. | 1 Hz, \(\frac{1}{2}\) sec |
Answer» C. \(\frac{1}{2}\) Hz, 1 sec | |
14. |
Find the Nyquist rate and Nyquist interval of sinc[t]. |
A. | 1 Hz, 1 sec |
B. | 2 Hz, 2 sec |
C. | \(\frac{1}{2}\) Hz, 2 sec |
D. | 2 Hz, \(\frac{1}{2}\)sec |
Answer» B. 2 Hz, 2 sec | |
15. |
Find the Nyquist rate and Nyquist interval of sin(2πt). |
A. | 2 Hz, \(\frac{1}{2}\) sec |
B. | \(\frac{1}{2}\) Hz, \(\frac{1}{2}\) sec |
C. | \(\frac{1}{2}\) Hz, 2 sec |
D. | 2 Hz, 2 sec |
Answer» B. \(\frac{1}{2}\) Hz, \(\frac{1}{2}\) sec | |
16. |
Consider a real-value based-band signal x(t), band limited to 10 kHz. The Nyquist rate for the signal y(t) = x(t) \(x(1+ \frac{t}{2})\) is |
A. | 60 kHz |
B. | 30 kHz |
C. | 15 kHz |
D. | 20 kHz |
Answer» C. 15 kHz | |
17. |
Consider the analog signal x(t) = 3 cos 100 πt. If the signal is sampled at 200 Hz, the discrete time signal obtained will be |
A. | 3 cos (πn/4) |
B. | 3 cos (πn/2) |
C. | 3 cos (πn) |
D. | 3 cos (πn/3) |
Answer» C. 3 cos (πn) | |
18. |
In Digital Filters, how many interpolated data points are inserted between samples performing 4X over sampling? |
A. | 2 |
B. | 3 |
C. | 4 |
D. | 5 |
Answer» D. 5 | |
19. |
Consider the two continuous-time signals defined below:\({x_1}\left( t \right) = \left\{ {\begin{array}{*{20}{c}}{\left| t \right|, - 1 \le t \le 1\;}\\{0,\;otherwise\;}\end{array},} \right.{x_2}\left( t \right) = \left\{ {\begin{array}{*{20}{c}}{1 - \left| t \right|, - 1 \le t \le 1\;}\\{0,\;otherwise\;}\end{array}} \right.\)These signals are sampled with a sampling period of T = 0.25 seconds to obtain discrete time signals x1[n] and x2[n], respectively. Which one of the following statements is true? |
A. | The energy of x1[n] is greater than the energy of x2[n]. |
B. | The energy of x2[n] is greater than the energy of x2[n]. |
C. | x1[n] and x2 have equal energies. |
D. | Neither x1[n] nor x2[n] is a finite-energy signal. |
Answer» B. The energy of x2[n] is greater than the energy of x2[n]. | |
20. |
Calculate the minimum sampling rate to avoid aliasing when a continuous-time signal is given by x(t) = 5 cos 400πt |
A. | 100 Hz |
B. | 250 Hz |
C. | 400 Hz |
D. | 20 Hz |
Answer» D. 20 Hz | |
21. |
Calculate the Nyquist rate for sampling when a continuous time signal is given by:x(t) = 5 cos 100πt +10 cos 200πt - 15 cos 300πt |
A. | 100 Hz |
B. | 150 Hz |
C. | 300 Hz |
D. | 600 Hz |
Answer» D. 600 Hz | |
22. |
Given a continuous time signal s(t) = 5cos(200 πt). The minimum sampling rate required to avoid aliasing will be |
A. | 50 Hz |
B. | 100 Hz |
C. | 200 Hz |
D. | 400 Hz |
Answer» D. 400 Hz | |
23. |
For the signal f(t) = 2 sin 9πt + sin 12 πt + sin 14 πt the minimum sampling frequency (in Hz) satisfying the Nyquist criterion is: |
A. | 14 sample / sec |
B. | 8 sample / sec |
C. | 12 sample / sec |
D. | None of the above |
Answer» B. 8 sample / sec | |
24. |
In flat-top sampling, a hold circuit is sometimes required. This hold circuit can be designed as a sampler followed by |
A. | A shunt capacitor |
B. | An envelope detector |
C. | Parallel RC circuit |
D. | A series resistance along with parallel RC circuit in shunt |
Answer» B. An envelope detector | |
25. |
Find out the Nyquist rate of the following signal: x(t) = 3 sin 10πt + 100 sin 400πt – 9 cos 110πt. |
A. | More than 5 Hz |
B. | More than 200 Hz |
C. | More than 110 Hz |
D. | Less than 110 Hz |
Answer» C. More than 110 Hz | |
26. |
If the sampling is carried out at rate higher than twice the highest frequency of the original single (fmax), then it is possible to receive the original signal from the sampled signal by passing it through |
A. | A high-pass filter with the cut-off frequency equal to fmax |
B. | A low-pass filter with the cut-off frequency equal to fmax |
C. | A high-pass filter with the cut-off frequency greater than fmax |
D. | A low-pass filter with the cut-off frequency lesser than fmax |
Answer» C. A high-pass filter with the cut-off frequency greater than fmax | |
27. |
A bandpass signal occupies the bandwidth 390 kHz to 410 kHz. What minimum sampling frequency would you use from the options given below, so as to avoid aliasing? |
A. | 40 kHz |
B. | 820 kHz |
C. | 41 kHz |
D. | 800 kHz |
Answer» D. 800 kHz | |
28. |
A 4 GHz carrier is amplitude-modulated by a low-pass signal of maximum cut off frequency 1 MHz. If this signal is to be ideally sampled the minimum sampling frequency should be nearly |
A. | 4 MHz |
B. | 4 GHz |
C. | 8 MHz |
D. | 8 GHz |
Answer» B. 4 GHz | |
29. |
A band limited signal is sampled at Nyguist rate, The signal can be recovered by passing the samples through |
A. | RC filter |
B. | envelope detector |
C. | PLL |
D. | ideal low pass filter with appropriate band width |
Answer» E. | |
30. |
Let \(x\left( t \right) = \;cos10\pi t + \cos \left( {30\pi t} \right)\) be sampled at 20Hz and reconstructed using an ideal LPF with fc of 20Hz. The frequency/frequencies present in reconstructed signal is/are |
A. | 5 Hz, 15 Hz only |
B. | 15 Hz only |
C. | 5 Hz only |
D. | 5, 10, 15 Hz only |
Answer» B. 15 Hz only | |
31. |
If analog sampling frequency of a band limited signal is doubled then corresponding digital sampling frequency will be |
A. | π |
B. | 2π |
C. | \(\frac{\pi }{2}\) |
D. | None of the above |
Answer» B. 2π | |
32. |
A system has a sampling rate of 50,000 samples per second. The maximum frequency of the signal it can acquire to reconstruct is |
A. | 25 kHz |
B. | 50 kHz |
C. | 100 kHz |
D. | 10 kHz |
Answer» B. 50 kHz | |
33. |
Let a signal x(t) = 3 cos (10πt) + cos (30πt) is sampled at a rate of 20 samples / second and reconstructed using on ideal low pass filter having cut off frequency of 20 Hz. The frequencies present in the reconstructed signal is / are. |
A. | 5 Hz and 15 Hz |
B. | 5 Hz, 10 Hz and 15 Hz only |
C. | 10 Hz and 15 Hz only |
D. | 5 Hz only |
Answer» B. 5 Hz, 10 Hz and 15 Hz only | |
34. |
A signal is passed through a LPF with cut-off frequency 10 kHz. The minimum sampling frequency is: |
A. | 5 kHz |
B. | 10 kHz |
C. | 20 kHz |
D. | 30 kHz |
Answer» D. 30 kHz | |
35. |
PAM signals are constructed by using a low pass filter of passband slightly greater than baseband to avoid aliasing. This avoids distortion : |
A. | True for flat top pulses |
B. | True if low pass filter has sharp cut off |
C. | Flat top pulses introduce envelope delay |
D. | Flat top pulses introduce amplitude distortion and delay |
Answer» E. | |
36. |
Consider the sampling of the band-pass signal, whose spectrum is as shown below. What minimum sampling frequency would you use from the options given below, so as to avoid aliasing? |
A. | 24 Hz |
B. | 26.5 Hz |
C. | 48 Hz |
D. | 212 Hz |
Answer» C. 48 Hz | |
37. |
In a DSP system: |
A. | Nyquist frequency is the same as the sampling frequency |
B. | Nyquist frequency is the same as folding frequency |
C. | Nyquist frequency is double the folding frequency |
D. | Nyquist frequency is half of oversampling rate |
Answer» C. Nyquist frequency is double the folding frequency | |
38. |
Let \({x_1}\left( t \right) \leftrightarrow {X_1}\left( \omega \right)\) and \({x_2}\left( t \right) \leftrightarrow {X_2}\left( \omega \right)\) be two signals whose Fourier Transforms are as shown in the figure below. In the figure, \(h\left( t \right) = {e^{ - 2\left| t \right|}}\) denotes the impulse response.For the system shown above, the minimum sampling rate required to sample y(t), so that y(t) can be uniquely reconstructed from its samples, is |
A. | \(2{B_1}\) |
B. | \(2\left( {{B_1} + {B_2}} \right)\) |
C. | \(4\left( {{B_1} + {B_2}} \right)\) |
D. | \(\infty\) |
Answer» C. \(4\left( {{B_1} + {B_2}} \right)\) | |
39. |
If the lower sideband overlaps the basebands, the distortion is called |
A. | Cross-Over distortion |
B. | Aliasing |
C. | Crosstalk |
D. | None of these |
Answer» C. Crosstalk | |
40. |
A signal m(t) = 3 cos (6000 πt) + 4 cos (7000 πt) + 5 cos (10000 πt) to be sampled. What is the minimum sampling rate for bandpass sampling for truth full representation: |
A. | 2000 Hz |
B. | 3000 Hz |
C. | 5000 Hz |
D. | 10000 Hz |
Answer» E. | |
41. |
Determine the Nyquist rate of signal x(t) = cos(200πt) × sin (300 πt) according to sampling theorem.(where ‘t’ indicates continuous-time domain) |
A. | 150 |
B. | 100 |
C. | 500 |
D. | 250 |
Answer» D. 250 | |
42. |
Consider the signal x(t) = cos(6πt) + sin(8πt), where t is in seconds. The Nyquist sampling rate (in samples/second) for the signal y(t) = x(2t + 5) is |
A. | 8 |
B. | 12 |
C. | 16 |
D. | 32 |
Answer» D. 32 | |
43. |
Assertion (A): Sampling theorem forms the basis for the relation between continuous-time signals and discrete-time signals.Reason (R): If the sampling is done at Nyquist rate, the signal x(t) can be reconstructed from the sample values x[n] = x[nTs]; −∞ ≤ n ≤ ∞. |
A. | Both (A) and (R) are true and (R) is the correct explanation of (A) |
B. | Both (A) and (R) are true, but (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, but (R) is not the correct explanation of (A) | |
44. |
Directions: The following items consist of two statements, one labeled as “Assertion(A)” and the other labeled as “Reason(R)”. You are to examine the two statements carefully and decide if the Assertion (A) and the Reason (R) are individually true and if so whether the reason is a correct explanation of the assertion. Select your answer to these items using the codes given below and mark your answer accordingly.Assertion (A): Lesser number of bits per code are required due to less number of quantization levels is DPCM.Reason (R): In this case, the difference between two successive samples is quantized which does not differ much in amplitude. |
A. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
B. | Both (A) and (R) are true, but (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, but (R) is not the correct explanation of (A). | |
45. |
Let x(t) be a signal with Nyquist rate ω0. Determine the Nyquist rate for y(t) = x(t)cos(ω0t) |
A. | ω0 |
B. | 2ω0 |
C. | 3ω0 |
D. | 2π |
Answer» D. 2π | |
46. |
An FM signal at 10.7 MHz. IF needs to be digitized for demodulation in a digital domain. If the bandwidth of this signal is 200 kHz, the maximum usable sampling frequency is |
A. | 200 kHz |
B. | 600 kHz |
C. | 400 kHz |
D. | 800 kHz |
Answer» D. 800 kHz | |
47. |
Assertion (A): Nyquist rate of sampling is the theoretical minimum sampling rate at which the signal can be sampled and still be reconstructed from its samples.Reason (R): When the Nyquist rate sampling is used, only an ideal low pass filter can be used to extract signal x(t) from sampled signal xs(t).Code: |
A. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
B. | Both (A) and (R) are true, but (R) is not the correct explanation of (A) |
C. | (A) is true, but (R) is false. |
D. | (A) false, but (R) is true |
Answer» B. Both (A) and (R) are true, but (R) is not the correct explanation of (A) | |
48. |
Arrange the Nyquist sampling interval of the signal in descending order(A) sin c(300t)(B) sin c(300t) + sin c2(300t)(C) sin c(200t)(D) sin c(200t) + sinc2(200t)(E) sin c(200t) + sin c(500t)Choose the correct answer from the options given below:(1) (A), (C), (B), (D), (E)(2) (C), (D), (E), (A), (B)(3) (C), (A), (D), (E), (B)(4) (A), (E), (D), (C), (B) |
A. | 1 |
B. | 2 |
C. | 3 |
D. | 4 |
Answer» D. 4 | |
49. |
For a discrete memory less source containing K symbols, the upper bound for the entropy is |
A. | 1/K |
B. | log2K |
C. | log10 K |
D. | log2 (1-K) |
Answer» C. log10 K | |
50. |
Assertion (A): A Non-Return to Zero (NRZ) type digital recording system is more common and efficient.Reason (R): It is possible to record twice the number of digits for the same number of pulses. |
A. | Both (A) and (R) are true and (R) is the correct explanation of (A). |
B. | Both (A) and (R) are true, but (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, but (R) is not the correct explanation of (A). | |