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3 years ago

Which change decreases the resistance of a piece

Physics

1 answer:

nika2105 [10]3 years ago

8 0

Explanation :

We know that the resistance of the wire is given by :

$R=\rho \dfrac{l}{A}$

Where

$\rho$ is the resistivity

l is the length of the wire

A is the area of the wire.

Another factor on which the resistance of wire depends is temperature. It is given by :

$R=R_{ref}[1+\alpha (T-T_{ref})]$

So, it is clear that the resistance of the wire is directly proportional to the temperature. It we want to decrease the resistance of the piece, its temperature should be decreased.

So, the correct option is (3) " decreasing the wire’s temperature ".

You might be interested in

Which person is weightless?

ahrayia [7]

Answer: Option (b) is the correct answer.

Explanation:

The force of gravity acting on an object helps in determining the weight of an object. But a place where there will be no gravity or have zero gravitational pull then it means the person will be weightless.

For example, force of gravity on moon is zero which means any object or person on moon will be weightless.

On the other hand, when a child is in the air as she plays on a trampoline then it means gravitational pull form the earth is acting on it. So, it will definitely has some weight.

Similarly, a scuba diver exploring a deep-sea wreck is under the ground where there will be force of gravity. Hence, it will also have some weight.

Thus, we can conclude that an astronaut on the Moon is the person who is weightless.

7 0

3 years ago

On your first day at work as an electrical technician, you are asked to determine the resistance per meter of a long piece of wi

Lostsunrise [7]

Answer:

$0.06\Omega/m$

Explanation:

Firstly, when you measure the voltage across the battery, you get the emf,

E = 13.0 V

In order to proceed we have to assume that the voltmeter offers no loading effect, which is a valid assumption since it has a very high resistance.

Secondly, the wires must be uniform. So the resistance per unit length is constant (say z). Now, even though the ammeter has very little resistance it cannot be ignored as it must be of comparable value/magnitude when compared to the wires. This is can seen in the two cases when currents were measured. Following Ohm's law and the resistance of a length of wire being proportional to it's length, we should have gotten half the current when measuring with the 40 m wire with respect to the 20 m wire ( $I=\frac{V}{R}$ ). But this is not the case.

Let the resistance of the ammeter be r

Hence, using Ohm's law we get the following 2 equations:

$\frac{13}{20z+r} =7.6$ .......(1)

$\frac{13}{40z+r} =4.5$ ......(2)

Substituting the value of r from (2) in (1), we have,

$13=152z+7.6\times\frac{13-180z}{4.5}$

which simplifying gives us, $z=0.0589\Omega/m\approx0.06\Omega/m$ (which is our required solution)

putting the value of z in either (1) or (2) gives us, r = 0.5325 $\Omega$

3 0

3 years ago

An electron is released from rest in a uniform electric field and accelerates to the north at a rate of 115 m/s squared. What ar

Iteru [2.4K]

The direction of the electric field would be south.

qE/m = 115
 E = 115*m/q 
 = 115 * 9.1 * 10^(-31) / 1.67*10^(-19) 
 = 762.87 * 10^(-12) 
 = 6.27 x 10^-10 N/C

Hope this answers the question. Have a nice day. Feel free to ask more questions.

6 0

3 years ago

Y'all I need this comon please give me a right answer

Natali [406]

It will be a virtual image that appears on the left side of the mirror

i hope this helps!

5 0

3 years ago

The current theory of the structure of the

Elza [17]

Answer: 91.4 J

Explanation:

Kinetic energy is the energy possessed by a body due to virtue of its motion.

K.E. = 0.5 m v²

Mass of the continent is given, m = 1.819 × 10²¹ kg

Side of the block of continent, s = 4150 km = 4150000 m

Depth of the block of continent, d = 38 km = 38000 m

(Mass = density × volume

m = 2780 kg/m³× (4150 × 10³ m)²× 38 × 10³ m = 1.819 × 10²¹ kg)

The continent is moving at the rate of, v = 1 cm /year = 0.01 m / 31556926 s = 3.17 × 10⁻¹⁰ m/s

⇒ K.E. = 0.5 × 1.819 × 10²¹ kg × (3.17 × 10⁻¹⁰ m/s)²= 91.4 J

Hence, mass of the continent has 91.4 J of kinetic energy.

5 0

3 years ago