csitfamilyElectric and Magnetism
66.n-equal capacitors are first connected in series and then in parallel. The the ratio of maximum to minimum capacitance [2075]
n2
1/n2
n
1/n
67.A wire of resistance 12Ω is bent to form a circle.The effective resistance between the two points on any diameter of circle is [2075]
12Ω
9Ω
6Ω
3Ω
68. The resistance of an ideal ammeter is [2075]
0
low
high
infinite
69. A 10 eV electron is circulating in a plane at right angles to a uniform field of magnetic induction 10-4, the orbital radius of the electron is [2075]
18cm
16cm
11cm
9cm
70. Whenever the magnetic flux linked with a coil changes,there is emf induced in the circuit the emf last [2075]
For a short time
For a long time
Forever
so long as the change in flux takes place
69. Wheat stone bridge is used to measure [2074]
emf
potential
current
resistance
70. Magnetism of a magnet [2074]
is zero at absolute zero temperature
increase with temperature
is maximum at curie temperature
becomes practically zero above curie temperature
71. The self inductance of coil is MH. If a current of 2a is flown. What is the magnetic flux through coil? [2074]
0.02 Wb
0.01 Wb
0.05 Wb
10 Wb
64. An isolated conducting sphere is given a positive charge. It's mass [2073]
increases
decreases
remains constant
may increase or decrease depending on the material
65. Three capacitors each of capacitance 3pF are connected in series. The net capacitance is [2073]
1μF
(1/3)μF
3μF
9μF
66. Kirchoff's voltage law is based on the principle of conservation of. [2073]
charge
energy
momentum
mass of charges
67. A charged particle is in a strong magnetic field. Then its kinetic energy [2073]
increase
decrease
remain constant
increase and become constant
68. The self-inductance of a straight wire is [2073]
zero
infinity
negative
positive
71. On increasing the reserve bias to a large value in a p-n junction diode, the current [2073]
increase slowly
remains fixed
decreases slowly
suddenly increases
67. A 25W, 120V lamp and 100W, 120V lamp are connected in series across a 120V line. Which lamp will burn more brightly[2072]
25W, 120V
100W, 120V
Both will have same brightness
Alternatively both may be bright, one at a time.
70. A 0 - 100mA resistance 1ft is to be converted to an ammeter in the range of 0-1A. We have to use shunt [2072]
1Ω
0.1Ω
0.111Ω
0.055Ω
68. A system of three charges may be in equilibrium . If they are placed[2071]
On a straight line
On corners of equilateral triangle
On three corners of rectangle
On the corners of a cube
69. The radius of Earth 6400 km. The capacitance is [2071]
6400 MF
6400 F
1 F
711 μF
70. Two wire of same material have lengths L and 2L and are cross reaction areas 4A and A respectively. The ratio of their specific resistance would be [2071]
1:1
1:8
8:1
1:2
71. The magnetic field induction inside a long solenoid is[2071]
zero
2μ0ni
μ0ni
μni
64. Three capacitor of capacitance 3µF, 9µF and 18µF are connected first in series and then I parallel. the ratio of C equivalent capacitance in two cases (CI/CP) will be[2070]/p>
1:15
15:1
1:1
1:3
65. Three equal registers each of resistance 'r' are connected to form a triangle. The equivalent resistance across any two comes of the triangle is.....[2070]
2r
r/3
2r/3
3r
66. The resistance of two lamp are in ratio of 1:2. Their wattage will be in the ratio of [2070]
1:2
2:1
4:1
1:4
67. The energy stored in 50mH inductor carrying a current of 4A is ....... [2070]
0.1 J
0.4 J
0.3 J
0.01 J
68. The alternating current in an LCR circuit is maximum when [2070]
XL = 0
XC = 0
XL = XC
73. A common emitter transistor amplifier has a current fain of 50. If the load resistance is 4 kΩ and the input resistance is 500 Ω. The voltage gain on the amplifier is ....... [2070]
400
6.2
500
300
64. Watt per ampere is the unit of [2069]
electric potential
electric field intensity
electric power
electric energy
65. Two wires A and B of equal radii are drawn from the same material. Their lengths are 1m and 2m respectively. The resistivity of A is. [2069]
less than that of B
equal to that of B
more than that of B
depends upon the amount of current flowing in wires
66. When a capacitor is added in series in an LCR circuit, the impedance of the circuit [2069]
increase
decrease
remain unchanged
increases or decreases depending upon the frequency of a.c
67. A cell of emf X if connected across a resist of R. The potentional difference across the wire is measured as Y. The internal resistance of the cell should be [2069]
X - (Y/R)
(X-Y)R
(X-Y)R/X
(X-Y)R/Y
