Related Questions

Hard steel is suitable for making permanent magnets because
A It has good residual magnetism
B Its hysteresis loop has large area
C Its mechanical strength is high
D Its mechanical strength is low
Materials used for making permanent magnets containing iron and nickel are made by __________ technique.
A Powder metallurgy
B Casting
C Forging
D None of these
Permanent magnets are normally made of
A Alnico alloys
B Aluminium
C Cast iron
D Wrought iron
The use of permanent magnets is. not made in
A magnetoes
B energy meters
C transformers
D loud-speakers
Addition of __________ to the steel helps in increasing the residual magnetism in steel used for making magnets.
A Chromium
B Nickel
C Tungsten
D Cobalt
Those materials are well suited for making permanent magnets which have ________ retentivity and ________ coercivity.
A Low, high
B High, high
C High, low
D Low, low
Alnico, an alloy used extensively for permanent magnets contains iron, nickel, aluminium and cobalt in the following ratio
A 50 : 20 : 20 : 10
B 40 : 30 : 20 : 10
C 50 : 20 : 10 : 20
D 30 : 20 : 30 : 20
Which of the following memories contains a thin film of magnetic material sandwitched between two permanent bias magnets?
A ROM
B Magnetic disk
C Core memory
D Bubble memory
E None of the above
The cutting speed for drilling aluminium, brass and bronze with carbon steel drills is _________ cutting speed for drilling mild steel with high speed steel drills.
A Equal to
B Less than
C More than
D None of these
High speed steel drills can be operated at about _________ the speed of high carbon steel drills.
A One-half
B One-fourth
C Double
D Four times

Next steps