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4 years ago

Which change decreases the resistance of a piece

Physics

1 answer:

nika2105 [10]4 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 ".

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A uniform magnetic field is perpendicular to the plane of a circular loop of diameter 13 cm formed from wire of diameter 2.6 mm

I am Lyosha [343]

Answer:

Rate of change of magnetic field is $3.466\times 10^3T/sec$

Explanation:

We have given diameter of the circular loop is 13 cm = 0.13 m

So radius of the circular loop $r=\frac{0.13}{2}=0.065m$

Length of the circular loop $L=2\pi r=2\times 3.14\times 0.065=0.4082m$

Wire is made up of diameter of 2.6 mm

So radius $r=\frac{2.6}{2}=1.3mm=0.0013m$

Cross sectional area of wire $A=\pi r^2=3.14\times0.0013^2=5.30\times 10^{-6}m^2$

Resistivity of wire $\rho =2.18\times 10^{-8}m$

Resistance of wire $R=\frac{\rho L}{A}=\frac{2.18\times 10^{-8}\times 0.4082}{5.30\times 10^{-6}}=1.67\times 10^{-3}ohm$

Current is given i = 11 A

So emf $e=11\times 1.67\times 10^{-3}=0.0183volt$

Emf induced in the coil is $e=-\frac{d\Phi }{dt}=-A\frac{dB}{dt}$

$0.0183=5.30\times 10^{-6}\times \frac{dB}{dt}$

$\frac{dB}{dt}=3.466\times 10^3=T/sec$

8 0

3 years ago

Which mixtures could be separated using evaporation? Check all that apply. fat in milk salt in ocean water mud in pond water but

salantis [7]

I would go with salt in ocean water as when you heat it and the water begins to evaporate it will leave the salt behind

Also water in mud as the water would evaporate and leave the mud residue behind

GOOD LUCK
BRAINLIEST IF HELPED

5 0

4 years ago

Read 2 more answers

In his psychology class, Professor Adams said that fear of spiders and snakes are common in humans, but fear of automobiles is n

Svetradugi [14.3K]

Answer:

Evolutionary

Explanation:

Because our ancestors were afraid of these poisonous spiders and snakes which lead to them to telling their kids of these dangers. Their kids will fear them without even encountering any and this will also be passed on to their future generations.

5 0

3 years ago

A 5 kg wooden block sitson a flat straight-away12 meters fromthe bottom of an infinitely long ramp, which has an angle of 20 deg

saveliy_v [14]

Answer:

(a) 19.71801m/s Velocity just before going up the ramp.

(b) 74.56338m.

Explanation:

We will solve it in two parts, first we will calculate time that 5kg wooden block would take to just reach ramp and with this time we will calculate final velocity that the wooden block would have in this time.

Second, we will calculate the component of velocity vector along inclined plane and the time that it would take for velocity to be 0 meters/s then with this time we will calculate the distance that inclined plane would travel along inclined plane.

Following formulas will be used.

$x(t) = \frac{1}{2} t^2 = 12m =16.2m/s^2 t^2$