Maharashtra Police Constable Question Paper set 4

1. If a square matrix of order 100 has exactly 15 distinct eigenvalues, then the degree of the minimal polynomial is

a) At least 15
b) At most 15
c) Always 15
d) Exactly 100

Ans:- a) At least 15

2. What is the probability that at most 5 defective fuses will be found in a box of 200 fuses, if 2% of such fuses are defective ?

a) 0.82
b) 0.79
c) 0.59
d) 0.52

Ans:- b) 0.79

3. For high speed reading and storing of information in a computer, the core shall be of

a) Ferrite
b) Piezoelectric
c) Pyroelectric
d) Ferromagnetic above 768*C

Ans:- a) Ferrite

4. Soft magnetic materials should have

a) Large saturation magnetization and large permeability
b) Low saturation magnetization and large permeability
c) Large saturation magnetization and low permeability
d) Low saturation magnetization and low permeability

Ans:- a) Large saturation magnetization and large permeability

5. Orbital magnetic moment of an electron, in an atom, is of the order of

a) 0.1 Bohr magneton
b) 1.0 Bohr magneton
c) 10 Bohr magneton
d) 100 Bohr magneton

Ans:- b) 1.0 Bohr magneton

6.When the temperature of a ferromagnetic material exceeds the Curie temperature, it behaves similar to a

a) Diamagnetic material
b) ferrimagnetic material
c) Paramamagnetic material
d) Antiferromagnetic material

Ans:- c) Paramamagnetic material

7. Photoconductivity is a characteristic of semiconductors. When light falls on certain semiconductors, it

a) Sets free electrons from some of the atoms, increasing the conductivity

b) Ejects electrons into space

c) Establishes a potential difference creating a source of EMF

d) Produces heat raising the temperature

Ans:- a) Sets free electrons from some of the atoms, increasing the conductivity

8.At temperatures above a limiting value, the energy of lattice vibrations, is a conductor, increases linearly with temperature so that resistivity increases linearly with temperature. In this region,this limiting value of temperatuire is called

a) Bernoulli temperature
b) Vurie temperature
c) Debye temparature
d) Neel temperature

Ans:- c) Debye temparature

9. Consider the following statements :

1. The critical magnetic field of a superconductor is maximum at abosolute zero.

2. Transition temperature of a superconductor is sensitive to its structure.

3. The critical magnetic field of a superconductor is zero at its critical temperature.

4. Superconductors show very high conductivity below the critical temperature.

Which of the above statements are correct?

a) 1, 2 and 3 only
b) 1, 2 and 4 only
c) 2, 3 and 4 only
d) 1, 3 and 4 only

Ans:- d) 1, 3 and 4 only

10.What is the correct sequence of the following materials in ascending order of their resistivity?

1. Iron
2. Silver
3. Constantan
4. Mica
5. Aliminium

Select the correct answer using the codes given below:

a) 2, 5, 1, 3 and 4
b) 4, 5, 3, 1 and 2
c) 2, 3, 1, 5 and 4
d) 4, 5, 1, 3 and 2

Ans:- a) 2, 5, 1, 3 and 4

11. In the first Causer network, with a pole at infinity, the first element must be

a) Series capacitor
b) Series inductor
c) Shunt capacitor
d) Shunt inductor

Ans:- b) Series inductor

12.The total magnetic moment

1. is called saturation magnetization.

2. depends on the number of magnetic dipoles per unit volume, the instant electric current and the area of the current loop.

Which of the above statements is/are correct?

a) 1 only
b) 2 only
c) Both 1 and 2
d) Neither 1 nor 2

Ans:- c) Both 1 and 2

13. Susceptibility of a diamagnetic material is

1. Negative
2. Positive
3. Dependent on the temperature
4. Independent of the temperature

Select the correct answer using the codes given below :

a) 1 and 3 only
b) 2 and 3 only
c) 1 and 4 only
d) 2 and 4 only

Ans:- c) 1 and 4 only

14. Consider the following statements :

1. The susceptibility x of diamagnetic materials is small and negative.

2. The susceptibility of para nad anti ferromagnetic materials is small but positive.

3. The susceptibility has a finite value for free space or air.

Which of the above statements are correct?

a) 1 and 2 only
b) 1 and 3 only
c) 2 and 3 only
d) 1, 2 and 3

Ans:- a) 1 and 2 only

15. Eddy current losses in transformer cores can be reduced by the use of

1. Solid cores
2. Laminated cores
3. Ferrites

Select the correct answer using the codes given below:

a) 2 and 3 only
b) 1 and 2 only
c) 1 and 3 only
d) 1, 2 and 3

Ans:- a) 2 and 3 only

16.The phenomenon of magnetostriction occurs when a ferromagnetic substance is magnetized resulting in

a) Heating
b) Small changes in its dimensions
c) Small changes in its crystal structure
d) Some chamge in its mechanical properties

Ans:- b) Small changes in its dimensions

17.Why type of defect causes F-centers in a crystal?

a) Stoichiometric defect
b) Metal excess defect due to anion vacancies
c) Metal exces defect due to extra xations
d) Frenkel defect

Ans:- b) Metal excess defect due to anion vacancies

18. Superconductivity is a material property associated with

a) Changing shape by stretching
b) Stretching without breaking
c) A loss of thermal resistance
d) A loss of electrical resistance

Ans:- d) A loss of electrical resistance

19.An atom in a crystal vibrates at a frequency, determined by

1.Crystal heat current
2.Crystal temperature
3.The stiffness of the bonds with neighbour atoms

Select the correct answer using the codes given below :

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- c) 3 only

20. In a connected graph, the total number of branches is b and the total number of nodes is n. Then number of linkes L of a co-tree is

a) b – n
b) b – n – 1
c) b + n – 1
d) b – n + 1

Ans:- d) b – n + 1

21.For a two-port reciprocal network, the three transmission parameters are A = 4, B= 7 and C = 5. What is the value of D ?

a) 9.5
b) 9.0
c) 8.5
d) 8.0

Ans:- b) 9.0

22.When 7/0.029 V.I.R cable is carrying 20 A, a drop of 1 V occurs every 12 m. The voltage drop in a 100 m run of this cable when it is carrying 10 A is nearly

a) 4.2 V
b) 3.2 V
c) 1.2 V
d) 0.42 V

Ans:- a) 4.2 V

23. Consider the following statements :

If a high Q parallal resonant circuit is loaded with a resistance

1. The circuit impedance reduces.
2. The resonant frequency remains the same.
3. The bandwidth reduces.

Which of the above statements is/are correct?

a) 3 only
b) 2 only
c) 1 only
d) 1, 2 and 3

Ans:- c) 1 only

24.The three non-inductive loads of 5 kW, 3 kW and 2 kW are connected in a star network between R, Y and B phases and neutral. The line voltage is 400 V. The current in the neutral wire is nearly

a) 11 A
b) 14 A
c) 17 A
d) 21 A

Ans:- a) 11 A

25. Kirchhoff’s current law is applicable to

1. Closed loops in a circuit
2. Junction in a circuit
3. Magnetic circuits

Which of the above is/are correct?

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- b) 2 only

26.Which of the following are satisfied in a non-Liner network?

1. Associative
2. Superposition
3. Homogeneity
4. Bilaterality

Select the correct answer using the codes given below :

a) 1 and 3 only
b) 1 and 4 only
c) 2 and 3 only
d) 2 and 4 only

Ans:- b) 1 and 4 only

27. Consider the following statements :

1. Network theorems are not derivable from Kirchhoff’s law.
2. To get the Norton currect, one has to short the current source.
3. Thevenin’s theorem is suitable for a circuit involving voltage sources and series connections.

Which of the above statements is/are correct?

a) 1, 2 and 3
b) 1 only
c) 2 only
d) 3 only

Ans:- d) 3 only

28.Consider the following statements with regard to Lissajous pattern on a CRO :

1. It is stationary pattern on the CRO.
2. It is used for precise measurement of frequency of a voltage signal.
3. The ratio between frequencies of vertical and longitudinal voltage signals should be an integer to have a steady Lissajous pattern.

Which of the above statements is/are correct?

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- a) 1 only

29.”Electric flux enclosed by a surface surrounding a charge is equal to the amount of charge enclosed”. This is the statements of

a) Faraday’s law
b) Lenz’s law
c) Modified Ampere’s law
d) Gauss’s law

Ans:- d) Gauss’s law

30.If a positively charged body is placed inside a spherical hollow conductor, what will be the polarity of charge inside and outside the hollow conductor?

a) Inside positive, outside negative
b) Inside negative, outside positive
c) Both negative
d) Both positive

Ans:- b) Inside negative, outside positive

31.Consider the following statements regarding Peer-to-Peer computing environment

1. In this system, clients and servers are not distinguished from one another.

2. All nodes distributed throughout the system (within) are considered Peers and each may act as either a client or a server.

3. Peer-to-Peer system assuredly offers certain advantages over the traditional client-server system.

4. Peer-to-Peer system is just a replica of the file-server system.

Which of the above statements are correct?

a) 1, 2, 3 and 4
b) 1, 2 and 3 only
c) 1 and 4 only
d) 2, 3 and 4 only

Ans:- b) 1, 2 and 3 only

32. What is the octal equivalent of (5621-125) 10?

a) 11774.010
b) 12765.100
c) 16572.100
d) 17652.010

Ans:- b) 12765.100

33. what is the hexadecimal representation of (657) 8 ?

a) 1 AF
b) D 78
c) D 71
d) 32 F

Ans:- a) 1 AF

34. In potential transformers, the secondary turns are increased slightly and the primary and secondary windings are wound as closely possible to compensate for

a) Phase angle and ratio error, respectively
b) Ratio and phase angle error, respectively
c) Any eddy currect loss and hysteresis loss, respectively
d) The hysteresis loss and eddy current loss, respectively

Ans:- b) Ratio and phase angle error, respectively

35. Consider the following statements with regard to Moving Iron(MI) instruments :

1. These instruments possess high operating torque.
2. These instruments can be used in ac and dc circuits.
3. Power consumption in these instruments isw lower for low voltage range.

Which of the above statements are correct?

a) 1 and 2 only
b) 1 and 3 only
c) 2 and 3 only
d) 1, 2 and 3

Ans:- a) 1 and 2 only

36.Which one of the following methods is used for the measurement of high resistances ?

a) Carey-Foster bridge methode
b) Substitution method
c) Loss of charge method
d) Potentiometer method

Ans:- c) Loss of charge method

37.Consider the following statements with regard to induction type watt meter :

1. Can be used on both ac and dc systems.
2. Power consumption is relatively low.
3. It is accurate only at stated frequency and temperature.

Which of the statements is/are correct?

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- c) 3 only

38. If n has the value 3, then the C language statements : a [+ +n] = n + +; assigns

a) 3 to a [5]
b) 4 to a [5]
c) 4 to a [4]
d) 5 to a [5]

Ans:- a) 3 to a [5]

39. A freewheeling diode in phase-controlled rectifiers

a) enables inverter operation
b) is responsible for additional reactive power
c) improves the line power factor
d) is responsible for additional harmonics

Ans:- c) improves the line power factor

40. Consider the following statements regarding electrical conductivity o :

1. it increases with temperature in semiconductors.

2.Its increase with temperature is exponential.

3. It increases in metals and their alloys, linearly with temperature.

Which of the above statements are correct ?

a) 1 and 2 only
b) 1 and 3 only
c) 2 and 3 only
d) 1, 2 and 3

Ans:- a) 1 and 2 only

41.Consider the following Components effectively control high frequencies ?

a) 1, 2 and 3
b) 1, 2 and 4
c) 1, 3 and 4
d) 2, 3 and 4

Ans:- c) 1, 3 and 4

43. A Wien Bridge Oscillator is suitable for

1. Audio frequency applications
2. Radio frequency applications
3. Vary low frequency applications

Which of the above frequency applications is/are correct?

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- a) 1 only

44. Which one of the following statements is correct?

LTI system is causal

a) If and only if its impulse response is non-zero for negative values of n.
b) If and only if its impulse response is non-zero for positive values of n.
c) If its impulse response is zero for negative values of n.
d) If its impulse response is zero for positive values of n.

Ans:- c) If its impulse response is zero for negative values of n.

45. Consider the following statements with respect to Discrete Fourier Transform (DFT):

1. It is obtained by performing a sampling operation in the time domain.

2. It transforms a finite duration sequence into a discrete frequency spectrum.

3. It is obtained by performing a sampling operation in both time and frequency domains.

Which of the above statements is/are correct?

a) 1 and 2 only
b) 2 and 3 only
c) 1 only
d) 3 only

Ans:- b) 2 and 3 only

46. A system has 14 poles and 2 zeros in its open-loop transfer function. The slope of its highest frequency asymptote in its magnitude plot is

a) – 40 dB/dec
b) -240 dB/dec
c) +40 dB/dec
d) +240 dB/dec

Ans:- b) -240 dB/dec

47. While forming a Routh array, the situation of a row of zeros indicates that the system

a) has symmetrically located roots
b) is stable
c) is insensitive to variationsin gain
d) has asymmetrically located roots

Ans:- a) has symmetrically located roots

48. A liner time-invariant control system with unsatisfactory steady state error is to be compensated. Which is/are the correct type of cascade compensation to be provided?

1. Lead
2. Lag
3. Lag-lead

select the correct answer using the codes given below :

a) 1 only
b) 2 only
c) 3 only
d) 1, 2 and 3

Ans:- b) 2 only

49.In a system, the damping coefficient is -2. the system response will be

a) Undamped
b) Oscillations with decreasing magnitude
c) Oscillations with increasing magnitude
d) Critically damped

Ans:- c) Oscillations with increasing magnitude

50. A 12-pole, 440 V, 50 Hz, 3-phase synchronous motor takes a line current of 100 A at 0.8 pf leading. Neglecting losses, the torque developed will be

a) 705 Nm
b) 1165 Nm
c) 1058 Nm
d) 525 Nm

Ans:- b) 1165 Nm