TNPSC Physics - Electricity and Magnetism
Exam Duration: 45 Mins Total Questions : 30
In electric supply lines in India, which parameter is kept constant?
- (a)
Voltage
- (b)
Current
- (c)
Frequency
- (d)
Power
Wich of the following is not correctly matched?
- (a)
Voltameter - potential difference
- (b)
Ammeter - eletriv current
- (c)
Potentiometer - emf
- (d)
Meter bridge - electrical resistance
Imagine a current carrying wire with the direction of current downward or into the page. The direction of magnetic field lines is
- (a)
clockwise
- (b)
anti-clockwise
- (c)
into the page
- (d)
out of the page
What is the difference between a CLF and an LED lamp?
1. To produce light, a CLF uses mercury vapour and phosphor while an LED lamp uses semiconductor material.
2. The average life span of a CFL is much longer than of and LED lamp.
3. A CFL is less energy-efficient as compared to an LED lamp.
Which of the statement(s) given above is/are correct?
- (a)
Only 1
- (b)
2 and 3
- (c)
1 and 3
- (d)
1, 2 and 3
Four wires of same material and of dimensions as mentioned below are stretched by a load of same magnitude separately. Which one of them will be elongated maximum?
- (a)
Wire 1m length and 2mm diameter
- (b)
Wire of 2 m length and 2mm diameter
- (c)
Wire of 5 m length and 105mm diameter
- (d)
Wire of 1 m length and 1 mm diameter.
A current carrying wire is known to produce magnetic lines of force around the conducting straight wire. The direction of the lines of force may be described by
- (a)
left hand thumb rule for up current and right hand thumb rule for down current
- (b)
right hand thumb rule for up current and left hand thumb rule for down current
- (c)
right hand thumb rule for both up and down currents
- (d)
left hand thumb rule for both up and down currents
'mho' is the unit of
- (a)
resistance
- (b)
specific resistance
- (c)
conductivity
- (d)
None of these
Indiscriminate disposal of used fluorescent electric lamps causes mercury pollution in the environment. Why is mercury used in the manufacture of these lamps?
- (a)
A mercury coating on the inside of the lamp makes the light bright white
- (b)
When the lamp is switched on, the mercury in the lamp causes the emission of ultra-violet radiations
- (c)
When the lamp is switched on, it is the mercury which converts the ultra-violet energy into visible light
- (d)
None of the statement given about is correct about the use of mercury in the manufacture of fluorescent lamps
Choke used to limit high frequency AC has
- (a)
air core
- (b)
iron core
- (c)
a paramagnetic core
- (d)
a diamagnetic core
Consider the following statements
An ordinary light bulb has a rather short life because the
1. filament wire is not uniform.
2. bulb cannot be evacuated completely.
3. wires supporting the filament melt at high temperatures.
Which one of the above statements are correct?
- (a)
1 and 3
- (b)
2 and 3
- (c)
1 and 2
- (d)
1, 2 and 3
A fuse is used in mains electric supply as a safety devices. Which one of the following statements about the fuse is correct?
- (a)
It is connected in parallel with the main switch
- (b)
It is made mainly from silver alloys
- (c)
It must have a low melting point
- (d)
It must a very high resistance
Which of the following quantities remain constant in a step-down transformer?
- (a)
Current
- (b)
Power
- (c)
Voltage
- (d)
None of these
A charge particle moves with velocity V in a uniform magnetic field B. The magnetic force experienced by the particle is
- (a)
always zero
- (b)
zero, if B and V are perpendicular
- (c)
zero, if B and V are parallel
- (d)
zero, if B and V are inclined at 45o
Alternating current can be measured by
- (a)
hot wire ammeter
- (b)
moving coil galvanometer
- (c)
tangent galvanometer
- (d)
None of the above
A current I flows through a potential difference V in an electrical circuit containing a resistance R. The product of V and I i.e., VI may be understood as
- (a)
resistance R
- (b)
heat generated by the circuit
- (c)
thermal power radiated by the circuit
- (d)
rate of change of resistance
AC power is transmitted from a power house at a high voltages
- (a)
power cannot be transmitted at low voltages
- (b)
the rate of transmission is faster at high voltages
- (c)
it is more economical due to less power loss
- (d)
a precaution against theft of transmission line
Consider the following statements
1. A comb moving through dry hair get electrically charged.
2. Electric lines of force are not closed but magnetic lines of force are closed.
Which of the statement(s) given above is/are correct?
- (a)
Only 1
- (b)
Only 2
- (c)
Both 1 and 2
- (d)
Neither 1 nor 2
By inserting a soft iron piece to solenoid, the strength of the magnetic field
- (a)
decrease
- (b)
increase
- (c)
first increase then decrease
- (d)
remains unchanged
Match the following lists
List I (Type of Cells) |
List II (Electro Motive Force) |
A. Voltaic cell | 1. 1.50 V |
B. Dry cell | 2. 2.00 V |
C. Lead container cell | 3. 1.08 V |
D. Battery of six cells | 4. 12.00 V |
- (a)
A B C D 1 2 3 4 - (b)
A B C D 3 1 2 4 - (c)
A B C D 4 3 2 1 - (d)
A B C D 3 4 2 1
The temperature at which a ferromagnetic material becomes paramagnetic is callled
- (a)
Curle temperature
- (b)
neutral temperature
- (c)
inversion temperature
- (d)
critical temperature
Dispersion can take place for
- (a)
transverse waves only but not for longitudinal waves
- (b)
longitudinal waves only but not for transverse waves
- (c)
Both transverse and longitudinal
- (d)
Neither transverse nor longitudinal waves
A device which is used in our TV set, Computer, Radio set for storing the electric charge, is
- (a)
resistor
- (b)
inductor
- (c)
capacitor
- (d)
conductor
Consider the following statements
1. A galvanometer is converted into an ammeter when we connect a low resistance in parallel.
2. A galvanometer is converted into a voltmeter when we connect a high resistance in series.
3. The conductivity of superconductor is infinite.
Which of the above statement(s) given above is/are correct?
- (a)
Only 1
- (b)
Only 2
- (c)
2, and 3
- (d)
1, 2 and 4
Light Emitting Diode (LED) con verts
- (a)
light energy into electrical energy
- (b)
electrical energy into light energy
- (c)
thermal energy into light energy
- (d)
mechanical energy into electrical energy
The electric current passing through a metallic wire produces heat because of
- (a)
collision of the atoms of the metal with each other
- (b)
collision of the conduction electron with the atoms of the metallic wire
- (c)
collision of conduction electrons with each other
- (d)
None of the above
Consider the following statements
1. A thermoelectric refrigerator works on Peltier effect.
2. The electrolyte in the dry cell is ammonium chloride.
3. The electrolyte in a car battery is sulphuric acid.
4. When a metal is heated, its resistance increases.
Which of the statements given above are correct?
- (a)
1,2 and 3
- (b)
2, 3 and 4
- (c)
1, 2 and 4
- (d)
1, 2 , 3 and 4
Consider the following statements
1. In a charged capacitor, the energy is stored in the electric field between the plates.
2. The dielectric constant of metals is infinite.
3. The field intensity on the surface of a charged conductor is directed normally to the surface.
4.Kirchhoff's voltage law is based on the law of conservation of energy.
Which of the statements given above are correct?
- (a)
1, 2 and 3
- (b)
2, 3 and 4
- (c)
2, 3 and 4
- (d)
1, 2 , 3 and 4
A magnetic needle is kept in non-uniform magnetic field. It experiences
- (a)
a force but not a torque
- (b)
a force and a torque
- (c)
a torque but not a force
- (d)
None of the above
The working of dynamo is based on principle of
- (a)
electromagnetic induction
- (b)
conversion of energy into electricity
- (c)
magnetic effect of current
- (d)
heating effect of current
The resistivity of wire
- (a)
increase with the length of the wire
- (b)
decrease with the area of cross section
- (c)
decrease with the length and increases with the cross-section of wire
- (d)
None of the above statement is correct