# Objective Type Question or MCQ of Electrical Circuits and Magnetic Fields page-9

121. A 100 watt, 250 V bulb will have more resistance than 60 watt, 250 V bulb.

a) True
b) False

Ans: (b)

122. The Kirchhoff᾽s laws fail in

a) Lumped parameters circuit
b) Distributed parameters circuit
c) Nonlinear circuits
d) Linear circuit
e) Bilateral circuit

Ans: (b)

123. When a circuit of 0.1 A is passed through a coil of 2000 turns, the MMF produced by the coil will be

a) 100 AT
b) 200 AT
c) 300 AT
d) 10 AT

Ans: (b)

124. Which of the following statements is correct?

a) The magnetic flux inside and exciting coil is greater than its outside surface.
b) The magnetic flux inside and exciting coil is same as on its outside surface.
c) The magnetic flux inside an exciting coil is lower than its outside surface.
d) The magnetic flux inside an exciting coil is zero

Ans: (b)

125. All the lines of magnetic flux on a coil produced by a uniform magnetic field are parallel and equidistance.

a) True
b) False

Ans: (a)

126. The magneto-motive force is

a) The flow of an electric current
b) The sum of all the current embraced by one line of magnetic field
c) The passage of magnetic field through an exciting coil
d) The voltage across the two ends of exciting coil

Ans: (b)

127. The “Ampere-Turns” are

a) The product of the number of the turns and current of the coil
b) The number of the turns of a coil through which current is flowing
c) The currents of all turns of the coil
d) The turns of transformer winding

Ans: (a)

128. The uniform magnetic field is

a) The field a single conductor
b) The field of set of parallel conductors
c) Field in which all line of magnetic flux are parallel and equidistant
d) None of the above

Ans: (c)

129. The reluctance of magnetic circuit depends on the length of magnetic flux path, cross-sectional area presented to the magnetic field and magnetic properties of material in which the magnetic field is generated

a) True
b) False

Ans: (a)

130. The change of cross-sectional area of conductor in magnetic field will affect

a) Resistance of conductor
b) Reluctance of conductor
c) (a) and (b) both in the same way
d) None of the above

Ans: (c)

131. The ferromagnetic materials have a relative permeability μr

a) Equal to one
b) Less than one
c) Far greater than one
d) Zero

Ans: (c)

132.The magnetic field can penetrate empty space.

a) True
b) False

Ans: (a)

133. What will be the current passing through the ring shaped air cored coil when number of turns is 900 and ampere-turns are 2700?

a) 3
b) 1.5
c) 6
d) 9

Ans: (a)

134. What will be the magnetic potential difference across the air gap of 4 cm length in the magnetic field of 400 AT/ m?

a) 4 AT
b) 8 AT
c) 16 AT
d) 20 AT

Ans: (c)

135. A certain amount of current flows through a ring-shaped coil with fixed number of turns. How does the magnetic induction B varies inside the coil if an iron core is threaded into coil without dimensional change of coil?

a) Increases
b) Decreases
c) Remains same
d) First increases and then decreases depending on the depth of iron core insertion

Ans: (a)

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