Olympiad Science - Fun with Magnets
Exam Duration: 45 Mins Total Questions : 30
P | Q | R |
---|---|---|
Magnets | Magnetic substances | Non-magnetic substances |
Articles from which of these groups can be attracted by magnets but cannot attract other objects?
- (a)
P
- (b)
Q
- (c)
R
- (d)
P and Q
Magnetic substances are attracted by magnets but cannot attract non-magnetic substances.
What is a natural magnet known as?
- (a)
Toroid
- (b)
Lodestone
- (c)
Haematite
- (d)
Solenoid
A natural magnet is known as lodestone
P | Q | R |
Magnets | Magnetic substances |
Non-magnetic substances |
After repeated rubbing with a magnet in the same direction, a piece of substance fails to get magnetised. To which group does it belong?
- (a)
P and Q
- (b)
Q and R
- (c)
Q
- (d)
R
A non-magnetic substance cannot be magnetised by rubbing it with a magnet or by any other method It can be placed in group R
P | Q | R |
---|---|---|
Magnets | Magnetic substances | Non-magnetic substances |
An object is repelled by a magnet. To which group does it belong?
- (a)
P
- (b)
Q
- (c)
R
- (d)
P and R
Only a magnet can be repelled by another magnet
P | Q | R |
---|---|---|
Magnets | Magnetic substances | Non-magnetic substances |
To which group does a ring made up of copper belong?
- (a)
P
- (b)
Q
- (c)
R
- (d)
Either Q or P
Copper is a non-magnetic material. It can be placed in group R.
Where is the force of attraction of a magnet the maximum
- (a)
At all sides
- (b)
All over the magnet
- (c)
At its poles
- (d)
At its centre
The force of attraction of a magnet is maximum at its poles.
In which direction does a magnet always point when suspended freely?
- (a)
South-West
- (b)
North-South
- (c)
East-West
- (d)
West-South
When suspended freely, a magnet always points towards the north-south direction.
What is the special property of magnetic substances?
- (a)
They are repelled by magnets.
- (b)
They are attracted by magnets
- (c)
They are both attracted and repelled by magnets.
- (d)
They cannot be made into magnets
The special property of magnetic substances is that they are attracted by magnets.
Rakeshhasone bar magnet, two iron pieces and all of them are of the same size and shape. Which of the following can be used for identifying them?
(i) Another magnet
(ii) A compass
(iii) A piece of thread
- (a)
Only (i) and (ii)
- (b)
Only (ii) and (iii)
- (c)
Only (i) and (iii)
- (d)
All the three
Rakesh has to suspend all the three pieces one after the other to check which one gets aligned in N-S direction. The one aligned is a magnet, the other two are iron pieces So, by using another magnet or a compass or a piece of thread, he can find out which piece is the magnet.
How is a compass useful to us?
- (a)
In finding the altitude of a place
- (b)
In finding only the north of a place
- (c)
In finding all the directions of a place
- (d)
In making artificial magnets
A compass can be used to find all the directions of a place.
Soft iron pieces are placed across the ends of bar magnets when stored. What are such pieces called?
- (a)
Preservatives
- (b)
Keepers
- (c)
Compasses
- (d)
Poles
Soft iron pieces which are placed across the ends of bar magnets when stored are called magnetic keepers.
Nikhilesh has a small piece of metal and a thread. He wants to find whether the metal is a magnet or not. Which of these things would he need?
- (a)
A piece of magnetic substance
- (b)
A magnet or a compass
- (c)
A piece of non-magnetic substance
- (d)
He does not require anything more
If the piece is a magnet, it comes to rest in the north-south direction when suspended freely with a thread. So, he does not need anything more.
Harish was asked to identify a piece of soft iron put in a basket of 10 magnets of the same shape and size. Which is the easiest way of identifying the iron piece at the earliest?
- (a)
By suspending the magnets one at a time.
- (b)
By conducting repulsion test using any two magnets at a time.
- (c)
By bringing another strong magnet near the basket
- (d)
By dropping all magnets into the water
Repulsion is the surest test of magnetism Harish can conduct the repulsion test by taking two magnets. In this way, he has conduct the test for a maximum of five times.
Which of the following ways will NOT cause a magnet to lose its magnetism?
- (a)
Heating it strongly over a flame
- (b)
Dropping it on the floor repeatedly
- (c)
Coating it with a layer of oil
- (d)
Hitting it with a hammer repeatedly
On coating a magnet with a layer of oil, the magnet does not lose its magnetism.
Bhavya placed a magnet near a metal ball and observed that the ball moved away. What does she conclude about the metal ball?
- (a)
It is a magnet
- (b)
It is made up of aluminium.
- (c)
It is made up of copper
- (d)
It is not a magnet
She concludes that the metal ball is a magnet because it moved away from the magnet due to repulsion.
Two magnets are placed close to each other as shown below. Which set will attract each other?
- (a)
- (b)
- (c)
- (d)
Like poles repel and unlike poles attract. The set in option (D) has both magnets placed with opposite poles facing each other. Hence, they attract each other.
In which of the following is a magnet used?
- (a)
Pin holder
- (b)
Plastic toy
- (c)
Car bumper
- (d)
Glass tumbler
A small piece of magnet in the pin holder attracts the pins.
A magnet in the form of a cube is placed on a piece of cork that floats on water. The cube is marked with four directions. W, X, Y and Z and the compass needle which points in the direction as shown in the figure.
Which of the following denotes the N - pole and S- pole of the magnet?
- (a)
N-Pole X-Pole W X - (b)
N-Pole X-Pole X Y - (c)
N-Pole X-Pole Y Z - (d)
N-Pole X-Pole Z W
Y denotes N pole as it faces the N pole of the compass needle. Similarly, Z denotes S pole of the magnet.
Which of the following figures does NOT show the poles correctly?
- (a)
- (b)
- (c)
- (d)
The poles in a circular m.agnet are at the top and at the bottom of the magnet.
Vishnu brings a magnet near 3 pins made up of different materials. PinsY and Z gets attracted whereas pin X remains in its places as shown below.
What materials are pins 'X', 'Y' and 'Z' made up of?
- (a)
Pin X Pin Y Pin Z Copper Iron Steel - (b)
Pin X Pin Y Pin Z Steel Nickel Aluminium - (c)
Pin X Pin Y Pin Z Copper Brass Cobalt - (d)
Pin X Pin Y Pin Z Iron Copper Brass
From the given figure, pin X is non-magnetic as it is not attracted by the magnet and it can be copper. Pin Y and pin Z are attracted by the magnet, so they are magnetic materials like iron, nickel, cobalt, steel, etc.
Which of the following is the correct method to prevent magnets from losing their magnetism?
- (a)
- (b)
- (c)
- (d)
A magnet kept in between two soft iron bars in a box is the correct method of handling and storing magnets.
Which one of the following is non-magnetic in nature?
- (a)
Iron
- (b)
nickel
- (c)
cobalt
- (d)
aluminium
Magnetic materials are those which get attracted towards a magnet. Aluminium is not attracted towards a magnet.
A bar shaped magnet was placed in a box containing pins. The magnet was removed.
The pins will stick___________ the magnet.
- (a)
all over
- (b)
on one side of
- (c)
to the two ends of
- (d)
to each other and
The pins are attracted more towards the region close to the two ends of a bar magnet. These two ends are the poles of the magnet
A freely suspended magnet will come to rest in
- (a)
any direction.
- (b)
East-West direction.
- (c)
vertical position.
- (d)
North-South direction.
One of the ends of a magnet will always point towards North and the other will be pointing at South. This end of the magnet which points towards North is the North seeking end or the North Pole (N) of the magnet. The other end is the South seeking end and is called the South Pole (S) of the magnet.
A magnet is used
- (a)
for finding directions.
- (b)
for holding a lid tightly on a box.
- (c)
on refriqerator doors.
- (d)
all of these.
A magnet has many uses in daily life.
Two similar poles of a magnet
- (a)
attract each other
- (b)
repel each other
- (c)
show no interaction
- (d)
join sideways to make a powerful magnet
The North Pole of one magnet will repel the North Pole of another magnet. The South Pole of one magnet will repel the South Pole of another magnet. But, the North Pole of one magnet will attract the South Pole of another magnet. The South Pole of one magnet will attract the North Pole of another magnet. Opposite poles of a magnet will attract each other but similar poles will repel each other.
There are two identical bars but one is made up of iron and the other is a magnet. We can easily find out which one is a magnet by
- (a)
suspending them with a thread separately and seeing which one takes the North-South direction
- (b)
observing that a bar magnet will attract the iron bar at either one of its poles and not all over the magnet bar
- (c)
both 'a' and 'b'.
- (d)
none of these
A magnet will show all the properties of a magnet like aligning in North-South direction and attracting iron
Which one of these will always point in the same direction?
- (a)
a magnetised needle attached to a cork that is suspended in water.
- (b)
a freely suspended magnet
- (c)
a magnetic compass needle
- (d)
all of these.
A magnet or a magnetised material if suspended freely will indicate North-South direction when it comes to rest
What will happen if a magnet is brought near a magnetic compass?
- (a)
there will be deflection in the needle
- (b)
the needle will rotate for some time
- (c)
the needle will not show any movement
- (d)
the like poles will attract and the North pole of the magnet will touch the south pole of the needle
The needle is on a pivot and can move freely. There will be interference from the magnet when brought closer to it and this will show as deflection in the needle.
Select the right match
ColumnA | Column B |
i) N-N | A) two poles |
ii) N-S | B) repulsion |
iii) magnet | C) attraction |
- (a)
i-C; ii-A; iii-B
- (b)
I-B; ii-A; iii-C
- (c)
i-A; ii-B; iii-C
- (d)
i-B; ii-C; iii-A
Like poles repel each other and unlike poles attract each other.