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elena-14-01-66 [18.8K]

3 years ago

7

Grinding quartz crystals down to produce sand is an example of a a. change of state. c. chemical reaction. b. chemical change. d

. physical change.

1 answer:

seraphim [82]3 years ago

5 0

D. A physical change

The makeup of it is still the same it's just ground up

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dedylja [7]

Answer:

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Explanation:

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What would be the most accurate way to describe resistance?

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Explanation:

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4 years ago

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2 years ago

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A (20*20) cm² loop has a resistance of 0.10 Ω. A magnetic field perpendicular to the loop is B = 4t - 2t², where B is in tesla a

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Answer with Explanation:

We are given that

Area of loop= $(20\times 20) cm^2=400\times 10^{-4} m^2$

$1 cm^2=10^{-4} m^2$

Resistance, R= $0.1\Omega$

B= $4t-2t^2$

We know that magnetic flux

$\phi=BA$

Emf , $E=\mid \frac{d\phi}{dt}\mid =\mid\frac{d(BA}{dt}\mid =\mid A\frac{dB}{dt}=400\times 10^{-4}\times \frac{4t-2t^2}{dt}\mid =\mid400\times 10^{-4}\times(4-4t)\mid$

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Substitute t=0 s

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Substitute t=1 s

Then, I= $1.6\mid (1-1)\mid$ =0

Substitute

t=2 s

Current, I= $1.6\mid(1-2)\mid$ =1.6 A

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3 years ago

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