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WorksheetsJKKN MONTHLY TEST -AUGUST -12th Em Physics
Total questions: 50
Worksheet time: 38mins
The expression for Torque on an electric dipole in an uniform electric field is __________
τ =E ×p
τ =Ep
τ=p.E
Which charge configuration Produces a uniform electric field?
Point charge
Uniformly charged infinite line
Uniformly charged infinite plane
Uniformly charged spherical shell
4 mC
5 mC
7 mC
8 mC
Total electric flux for the following closed surface which is kept inside water
A
B
C
D
1=4<2<3
2=4<3<1
2=3<1<4
3<1<2<4
1 uF
3 uF
2 uF
1/4 uF
A parallel plate capacitor stores a charge Q at a voltage V. Suppose the area of the parallel plate capacitor and Distance between the plates are each doubled then which is the quantity that will change?
Capacitance
Charge
Voltage
Energy density
D<C<B<A
D>C>B>A
A<B=C<D
C<A=B<D
A
B
C
D
5
1/5
11/25
25/11
A
B
C
D
If one of the resistors in a parallel circuit is removed, the total resistance will be
zero
decreases
increases
constant
The resistance of the wire varies inversely as
area of cross section
resistivity
length
temperature
The melting point of tungsten is
3280 o C
3580 o C
3380 o C
3680 o C
Nichrome wire is used as the heating element beacause it has
low specific resistance
low melting point
high specific resistance
high conductivity
The following graph shows current
versus voltage values of some unknown
conductor. What is the resistance of
this conductor?
2 ohm
4 ohm
8 ohm
1 ohm
A toaster operating at 240 V has a
resistance of 120 Ω. Its power is
400 W
2 W
480 W
240 W
Yellow – Green – Violet – Gold
Yellow – Violet – Orange – Silver
Violet – Yellow – Orange – Silver
Green – Orange – Violet - Gold
In India electricity is supplied for
domestic use at 220 V. It is supplied at
110 V in USA. If the resistance of a 60W
bulb for use in India is R, the resistance
of a 60W bulb for use in USA will be
R
2R
R/4
R/2
The temperature coefficient of
resistance of a wire is 0.00125 per °C.
At 20°C, its resistance is 1 Ω. The
resistance of the wire will be 2 Ω at
800 °C
700 °C
850 °C
820 °C
The internal resistance of a 2.1 V cell
which gives a current of 0.2 A through
a resistance of 10 Ω is
0.2Ω
0.5Ω
0.8Ω
1.0Ω
In Joule’s heating law, when R and t are
constant, if the H is taken along the y
axis and I2 along the x axis, the graph is
straight line
parabola
circle
ellipse
Which is the most commonly used conductor in electrical circuits?
copper
aluminium
silver
gold
If the current flows in same direction the force between the conductors are _________________
greater
lesser
attractive
repulsive
moving coil galvanometer is used to find the ______________ in the circuit.
current
voltage
key
potential difference
Inside the magnet, the direction of field lines is from its
north to south
south to north
mag. field do not move inside a magnet.
none
10. The SI unit of magnetic field is _________
newton
coulomb
Tesla
Watt
superconductors will behave as __________ materials below transition temperature
none of the options
paramagnetic
ferromagnetic
diamagnetic
Aurora australis happens due to __________
mass of earth
density of earth
sunlight
solar wind
When a bar magnet is cut into 2 pieces along its length its pole strength will be _________
halved
zero
twice
same
A resistor is connected to an AC power supply. On this circuit, the current
leads the voltage by 90°.
lags the voltage by 90°.
is in phase with the voltage.
none of the given answers
A circular coil of radius 5 cm and 50 turns carries a current of 3 ampere. The magnetic dipole moment of the coil is nearly
1.0 A m2
1.2 A m2
0.5 A m2
0 .8 A m2
A thin insulated wire forms a plane spiral of N =100 tight turns carrying a current I = to 8 m A. The radii of inside and outside turns for a = 50 mm and b =100 mm respectively. The magnetic induction at the centre of the spiral is
5 μ T
7 μ T
8 μ T
10 μ T
Three wires of equal lengths are bent in the form of loops. One of the loops is circle, another is a semicircle and the third one is a square. They are placed in a uniform magnetic field and same electric current is passed through them. Which of the following loop configuration will experience greater torque?
Circle
Semi circle
Square
All of them
A non conducting charged during carrying a charge of q, mass m and radius R is rotated about its axis with constant angular speed ω. Find the ratio of its magnetic moment with angular momentum is
q/m
2q/m
q/2m
q/4m
The vertical component of Earth's magnetic field at a place is equal to the horizontal component. What is the value of angle of dip at this place?
30°
45°
60°
90°
In a serious resonant RLC circuit the voltage across 100 ohm resistor is 40 volt. The resonant frequency is 250 radian per second. If the value of C is 4 microfarad then the voltage across L is
600 V
4000 V
400 V
1 V
A step down transformer reduces the supply voltage from 220 volt to 11 volt, and increases the current from 6 A to 100 A. Then its efficiency is
1.2
0.83
0.12
0.9
In a transformer the number of turns in the primary and the secondary are 410 and 1230 respectively. If the current in primary is 6 A,then that in the secondary coil is
2 A
18 A
12 A
1A
In a serious RL circuit the resistance and inductive reactance are the same, then the phase difference between the voltage and current in the circuit is
π/4
π/2
π/6
0
When the current changes from 2 A to -2 A in 0.05 s, any EMF 8 V is induced in a coil. The coefficient of self induction of the coil is
0.2 H
0.4 H
0.8 H
0.1 H
An inductor of 20 mH,a capacitor of 50 microfarad and a resistor of 40 ohm are connected in series across a source of emf V =10sin340 t.The power loss in AC circuit is
0.76 W
0.89 W
0.46 W
0.76 W
The turn ratio (r) for a step-up transformer is
r = 0
r > 1
r < 1
r = 1
