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WorksheetsPHYSICS 3
Total questions: 55
Worksheet time: 10mins
What should be the core of an electromagnet?
soft iron
hard iron
rusted iron
none of above
Who has stated the Right hand Thumb Rule?
Orsted
Fleming
Einstein
Maxwell
In all the electrical appliances, the switches are put in the
live wire
earth wire
neutral wire
all of above
What is the condition of an electromagnetic induction?
there must be a relative motion between the coil of wire and galvanometer
there must be a relative motion between the galvanometer and a magnet
there must be a relative motion between galvanometer and generator
there must be a relative motion between the coil of wire and a magnet
No force acts on a current carrying conductor when it is placed-
perpendicular to the magnetic field
parallel to the magnetic field
far away from the magnetic field
inside a magnetic field
What is that instrument which can detect the presence of electric current in a circuit?
galvanometer
motor
generator
none of above
Which device produces the electric current?
generator
galvanometer
ammeter
motor
What is electromagnetic induction?
the process of charging a body
The process of rotating a coil of an electric motor.
producing induced current in a coil due to relative motion between a magnet and the coil
The process of generating magnetic field due to a current passing through a coil.
What happens to the current in short circuit?
reduces substantially
does not change
increases heavily
vary continuously
An alpha particle is diverted towards west is deflected towards north by a field. The field is magnetic. What will be the direction of field?
Towards south
towards east
downward
upward
The north pole of Earth’s magnet is in the:
Geographical South
Geographical East
Geographical West
Geographical North
A soft iron bar is inserted inside a current-carrying solenoid. The magnetic field inside the solenoid:
Will decrease
Will increase
Will become zero
Will remain the same
A current carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor:
From left to right
From bottom to top
From top to bottom
From right to left
An induced emf is produced when a magnet is moved into a coil. The magnitude of induced emf does not depend on:
The speed with which the magnet is moved
The number of turns of the coil
The resistivity of the wire of the coil
The strength of the magnet
A positive charge is moving towards a person. The direction of magnetic field lines will be in
Clockwise direction
Anticlockwise direction
Vertically upward direction
Vertically downward direction
A fuse should always be placed in the
Live wire of the main circuit
Neutral wire of the main circuit
Earth wire of the main circuit
Bothe live and neutral wire of the main circuit.
The shape of the magnetic field lines produced by a current carrying conductor are:
Straight lines
Concentric circles
Concentric ellipse
Concentric parabolas
An electric motor is a device which transforms
Mechanical energy into electrical energy
Electrical energy into mechanical energy
Kinetic energy into potential energy
Electrical energy into Potential energy
The frequency of electricity produced by DC generator is equal to
0 Hz
100 Hz
50 Hz
200 Hz
Inside the magnet, the field lines moves
from north to south
from south the north
away from south pole
away from north pole
Relative strength of magnetic field at a point in the space surrounding the magnet is shown by the
thickness of magnet
degree of closeness of the field.
length of magnet
resistance offered by the surroundings
The best material to make permanent magnets is
aluminium
soft iron
copper
none of these
The magnetic field is the strongest at
middle of the magnet.
north pole.
south pole.
both poles.
Magnetic lines of force inside current carrying solenoid are
parallel inside the solenoid and circular at the ends.
along the axis and are parallel to each other.
perpendicular to axis.
circular.
The magnitude of the induced current due to the relative motion of coil and a magnet does not depend on...
speed of the relative motion
number of turns of coil
resistivity of wire of coil
pole strength of the magnet
_____ current line is connected to the air-conditioning machine.
20 A
15 A
10 A
5 A
If many appliances are connected in a circuit, _____ may occur.
short-circuit
long-circuit
over loading
explosion
In our domestic electric supply, we use following three colours of insulation cover on wires:
Red, blue, green
Red, yellow, blue
Black, green, yellow
Red, black, green
If an incident ray passes through the focus, the reflected ray will
pass through the pole
be parallel to the principal axis
retrace its path
pass through the centre of curvature
When light falls on a smooth polished surface, most of it
is reflected in the same direction
is reflected in different directions
is scattered
is refracted into the second medium
Focal length of a concave mirror is
negative
positive
depends on the position of object
epends on the position of image
Which mirroji can produce a virtual, erect and magnified ifhage of an object?
Convex mirror
Plane mirror
Concave mirror
Both concave and convex mirrors
If the image is formed in front of the mirror, then the image distance will be
positive or negative depending on the size of the object
neither positive nor negative
positive
negative
Focal length of plane mirror is
At infinity
Zero
Negative
None of these
Image formed by plane mirror is
Real and erect
Real and inverted
Virtual and erect
Virtual and inverted
A concave mirror gives real, inverted and same size image if the object is placed
At F
At infinity
At C
Beyond C
A concave mirror gives virtual, refract and enlarged image of the object but image of smaller size than the size of the object is
At infinity
Between F and C
Between P and F
At E
The angle of incidence for a ray of light having zero reflection angle is
30°
0
90°
45°
For a real object, which of the following can produce a real image?
Plane mirror
Concave mirror
Concave lens
Convex mirror
point of incidence and reflected ray are
perpendicular
same line
same surface
same line
principal focus of the concave mirror
diverge
converge
move away
none of these
distance PC is equal to ___________________
radius of curvature
principal axis
pole
centre of curvature
direction of propagation of light
beam of light
pole
reflection of light
ray of light
The nature of image formed by a convex mirror when the object distance from the mirror is less than the distance between pole and focal point (F) of the mirror would be
real, inverted and diminished in size
real, inverted and enlarged in size
virtual, upright and diminished in size
virtual, upright and enlarged in size
Which of the following mirror is used by a dentist to examine a small cavity?
Convex mirror
Plane mirror
Concave mirror
Combination of convex and concave mirror
The image formed by a convex lens can be
virtual and magnified
virtual and diminished
virtual and of same size
virtual image is not formed
A current carrying conductor is held in exactly vertical direction. In order to produce a clockwise magnetic field around the conductor, the current should be passed in the conductor:
From top to bottom
From left to right
From bottom to top
From right to left
The force exerted on a current carrying wire placed in a magnetic field is zero when the angle between wire and the direction of magnetic field is:
45o
60o
90o
180o
An induced emf is produced when a magnet is moved into a coil. The magnitude of induced emf does not depend on:
The speed with which the magnet is moved
The number of turns of the coil
The resistivity of the wire of the coil
The strength of the magnet
A positive charge is moving towards a person. The direction of magnetic field lines will be in
Clockwise direction
Anticlockwise direction
Vertically upward direction
Vertically downward direction
Which of the following virus causes COVID-19?
Ebola
SARS-CoV-2
Hantavirus
MERS
corona belongs to which virus group
RNA
DNA
body
none of the above
Corona belongs to which family below
Priocoronavirinae
Orthocoronavirinae
Orthocoronafungi
none of the above
The novel coronavirus originated from Huanan Seafood Wholesale Market. In which Chinese province is this market located?
Beijing
Hubei
Hainan
Sichuan
Which of the following symptoms are not observed in a COVID-19 patient?
Fever
Cough
Breathing difficulties
Big Boils on the skin
