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3 years ago

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A Si sample contains 1016 cm-3 In acceptor atoms and a certain number of shallow donors, the In acceptor level is 0.16 eV above

Ev , and EF is 0.26 eV above Ev at 300 K. How many (cm-3) In atoms are un-ionized (i.e., neutral)

2 answers:

matrenka [14]3 years ago

6 0

Answer:

Explanation: see attachment below

creativ13 [48]3 years ago

5 0

Answer:

6.5 × 10¹⁵/ cm³

Explanation:

Thinking process:

The relation $N_{o} = N_{i} * \frac{E_{f}-E_{i} }{KT}$

With the expression Ef - Ei = 0.36 × 1.6 × 10⁻¹⁹

and ni = 1.5 × 10¹⁰

Temperature, T = 300 K

K = 1.38 × 10⁻²³

This generates N₀ = 1.654 × 10¹⁶ per cube

Now, there are 10¹⁶ per cubic centimeter

Hence, $N_{d} = 1.65*10^{16} - 10^{16} \\ = 6.5 * 10^{15} per cm cube$

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The 10-lb block is pressed against the spring so as to compress it 2 ft when it is at a point A. If the plane is smooth, determi

leva [86]

Answer:

The distance measure from the wall = 36ft

Explanation:

Given Data:

w = 10

g =32.2ft/s²

x = 2

Using the principle of work and energy,

T₁ +∑U₁-₂ = T₂

0 + 1/2kx² -wh = 1/2 w/g V²

Substituting, we have

0 + 1/2 * 100 * 2² - (10 * 3) = 1/2 * (10/32.2)V²

170 = 0.15528V²

V² = 170/0.15528

V² = 1094.796

V = √1094.796

V = 33.09 ft/s

But tan ∅ = 3/4

∅ = tan⁻¹3/4

= 36.87°

From uniform acceleration,

S = S₀ + ut + 1/2gt²

It can be written as

S = S₀ + Vsin∅*t + 1/2gt²

Substituting, we have

0 = 3 + 33.09 * sin 36.87 * t -(1/2 * 32.2 *t²)

19.85t - 16.1t² + 3 = 0

16.1t² - 19.85t - 3 = 0

Solving it quadratically, we obtain t = 1.36s

The distance measure from the wall is given by the formula

d = VCos∅*t

Substituting, we have

d = 33.09 * cos 36. 87 * 1.36

d = 36ft

5 0

3 years ago

Read 2 more answers

For some metal alloy it is known that the kinetics of recrystallization obey the Avrami equation, and that the value of k in the

JulsSmile [24]

Answer:

t = 1456.8 sec

Explanation:

given data:

contant k = 2.60*10^{-6}

rate of crystallization is 0.0013 s-1

rate of transformation is given by

$r = \frac{1}{t_0.5}$

use specifies value to solve $t_0.5$

it is ime required for 50% tranformation

$r = \frac{1}{.0013}=769.2 sec$

Avrami equation is given by

$y = 1 - e^{-kt^n}$

$0.5 = 1 - e^{-kt_0.5^n}$

$1-0.5 = e^{-kt_0.5^n}$

$ln (1 - 0.5) = -kt_0.5^n$

$ln \frac{ln (1 - 0.5)}{-k} = nln t_0.5$

$n = \frac{ ln \frac{ln (1 - 0.5)}{-k}}{ln t_0.5}$

$n = \frac{ ln \frac{ln (1 - 0.5)}{-2.60*10^{-6}}}{ln 769.2}$

n = 1.88

second degree of recrystalization may be determine by rearranging original avrami equation

$t = [\frac{-ln(1-y)}{k}]^{1/n}$

for 90%completion

$t = [\frac{-ln(1-0.9)}{2.60*10^{-6}}]^{1/1.88}$

t = 1456.8 sec

5 0

3 years ago

tresset_1 [31]

Answer:

A because i know thats it

8 0

3 years ago

A steam turbine has isentropic efficiency of 0.8. Isentropically, it is supposed to deliver work of 100 kW. What is the actual w

trapecia [35]

Answer:

80 kW; 11 kW; 8 kW; 0.6

Explanation:

Part 1

Isentropic turbine efficiency:

$\eta_t = \frac{\text{Real turbine work}}{\text{isentropic turbine work}} = \frac{W_{real}}{W_s}$

$W_{real} = \eta_t*W_s$

$W_{real} = 0.8*100 kW$

$W_{real} = 80 kW$

Part 2

Coefficient of performance COP is defined by:

$COP = \frac{Q_{out}}{W}$

$Q_{out} = W*COP$

$Q_{out} = 5 kW*2.2$

$Q_{out} = 11 kW$

Part 3

(a)

Energy balance for a refrigeration cycle gives:

$Q_{in} + W = Q_{out}$

$3 kW + 5 kW = Q_{out}$

$8 kW = Q_{out}$

(b)

$COP = \frac{Q_{in}}{W}$

$COP = \frac{3 kW}{5 kW}$

$COP = 0.6$

3 0

3 years ago

How to find magnitude of net electric charge when current flows through a capacitor with initial charge?

Ksenya-84 [330]

Answer:

Q=q $e^{-t/RC}$

also

q=it

Explanation:

How to find magnitude of net electric charge when current flows through a capacitor with initial charge?

A capacitor is a device used in storing electric charges. The unit of capacitance is measured in farad

To find the magnitude of net electric charge in a capacitor, we use the following relation

Q=q $e^{-t/RC}$

Q=the magnitude of net electric charge in coulombs

t=the time for an electron tpo pass through the capacitor

R=the resistance of the capacitor , measured in ohms

C=the capacitance of the capacitor measures in Farad

q=initial quantity of charge

Having all the parameters above will make it possible to determine the net electric charge

Recall also that

q=it

quantity (coulombs)=current*time(s)

3 0

3 years ago