Question is ⇒ Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes, Options are ⇒ (A) 1/9 times, (B) 3 times, (C) 9 times, (D) unchanged, (E) , Leave your comments or Download question paper.

Question is ⇒ Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes, Options are ⇒ (A) 1/9 times, (B) 3 times, (C) 9 times, (D) unchanged, (E) , Leave your comments or Download question paper. Previous question Next question


Q1.	Copper wire of certain length and resistance is drawn out to three times its length without change in volume, the new resistance of wire becomes
A.	1/9 times [Wrong Answer]
B.	3 times [Wrong Answer]
C.	9 times [Correct Answer]
D.	unchanged [Wrong Answer]
View Answer 9 -5 Explanation:- Answer : C Discuss it below : KARTHIK Karthik Said on 2018-04-10 05:57:12 When a wire is stretched, its volume will remain the same. Since Volume = Area x length, given that length has increased three times, the area will be decreased by 3. So, new length = 3L. New Area = A/3 Resistance is proportional to Length/Area. New resistance is proportional to 3L/(A/3) New resistance = 9R !! OOPS Login [Click here] is required to post your answer/result Help other students, write article, leave your comments

Previous question Next question

Also Read Similar Questions Below :

⇒ In the case of direct current
magnitude and direction of current remains constant
magnitude and direction of current changes with time
magnitude of current changes with time
magnitude of current remains constant

⇒ Through a metallic conductor an electric current is due to drift of
Free electrons
Positive and negative ions
Free electrons and holes
Protons

⇒ In a lamp load when more than one lamp are switched on the total resistance of the load
increases
decreases
remains same
none of the above

⇒ An instrument which detects electric current is known as
voltmeter
rheostat
wattmeter
galvanometer

⇒ When electric current passes through a bucket full of water, lot of bubbling is observed. This suggests that the type of supply is
A.C.
D.C.
any of above two
none of the above

⇒ A 100 watt light bulb burns on an average of 10 hours a day for one week. The weekly consumption of energy will be ____unit/s.
7
70
0.7
0.07

⇒ The thickness of insulation provided on the conductor depends on
the magnitude of voltage on the conductor
the magnitude of current flowing through it
both (a) and (b)
none of the above

⇒ The flow of current in solids is due to
electrons
electrons and ions
atoms
nucleus

⇒ Seebeck effect is inverse of
Peltier effect
Joule's effect
Thomson's effect
None of these

⇒ The electrical conductivity of metals is typically df the order of (in ohm^-1 m^-1)
10⁷
10⁵
10^-4
10^-6

⇒ A field of force can exist only between
two molecules
two ions
two atoms
two metal particles

⇒ The thermo electric power at the neutral temperature is
Negative
Zero
Positive
None of these

⇒ For testing appliances, the wattage of test lamp should be
very low
low
high
any value

⇒ If a very flexible wire is laid out in the shape of a hair pin with its two ends secured, what shape will the wire tend to assume if a current is passed through it?
Parabolic.
Straight line.
Circle.
Ellipse.

⇒ The substances which have a large number of free electrons and offer a low resistance are called
insulators
inductors
semi-conductors
conductors

⇒ In gases the flow of current is due to
electrons only
positive ions only
electrons and positive ions
electrons, positive ions and negative ions

⇒ Current velocity through a copper conductor is
nearly 3 X 10⁹ m/s.
of the order of a few micro m/s.
independent of current strength.
the same as propagation velocity of electric energy.

⇒ One coulomb charge equals the charge on
6.24 x 10¹² electrons
6.24 x 10⁴ electrons
6.24 x 10¹⁶ electrons
6.24 x 10¹⁸ electrons

⇒ The fuse-wire is made of
Copper
Tungsten
Lead-tin alloy
Nichrome

⇒ In an electric kettle water boils in 10 mjnutes. It is required to boil the boiler in 15 minutes, using same supply mains
length of heating element should be decreased
length of heating element should be increased
length of heating element has no effect on heating if water
none of the above

⇒ Two bulbs 100 W, 250 V and 200 W, 250 V are connected in series across a 500 V line. Then
100 W bulb will be fused
200 W bulb will be fused
Both bulbs will be fused
No bulb will be fused

⇒ Which of the following relation is not correct?
P = ^V
^R²

P = VI
I = √P/R
V = √PR

⇒ A 200 W, 230 V lamp is connected across 115 V supply. The lamp will draw power
slightly more than 50W.
slightly less than 50W.
exactly 100 W.
exactly 50W.

⇒ The quantity in electricity analogous to friction in linear mechanical motion is
Resistance
Potential
Charge
Inductance

⇒ "The total electric flux through any closed surface surrounding charges is equal to the amount of charges enclosed."
The above statement is based on
Maxwell's law.
Ampere's law.
Gauss's law.
Coulomb's law.

⇒ Pure metals generally have
high conductivity and low temperature coefficient.
high conductivity and large temperature coefficient.
low conductivity and zero temperature coefficient.
low conductivity and high temperature coefficient.

⇒ The thermal speed of electrons is of the order of
1 m/s
10^-3 m/s
10⁶ m/s
3 x 10⁸ m/s

⇒ Identify the set in which all the three materials are good conductors of electricity
Cu, Ag, Au
Cu, Si and diamond
Cu, Hg and NaC1
Cu, Ge and Hg

⇒ Two heaters, rated at 1000 W, 250 V each are connected in series across a 250 V, 50 Hz ac mains. The total power drawn from the supply would be____ W.
1,000
500
250
2,000

⇒ When subjected to a transverse electric field, cathode rays move
Down the potential gradient
Up the potential gradient
Along a hyperbolic path
Along a circular path