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2 years ago

12

X rays are used in hospital to locate in the patients bones.If the x rays of wavelength of 2×10 to the power negative nine m tra

vel at a speed of 3×10 to the power eight m/s in air, what will be it's frequency?

1 answer:

jasenka [17]2 years ago

8 0

Answer:1.5×10 to the power of 17(unit-Hertz/H)

Explanation:V=F×Wavelength

F=V/Wavelength=3×10 to power/2×10 to power of -9=1.5×10 to power of 17

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61. A physics student has a single-occupancy dorm room. The student has a small refrigerator that runs with a current of 3.00 A

Mademuasel [1]

Answer:

Part a)

$percentage = 21.3$ %

Part b)

$percentage = 2.13 \times 10^{-5}$ %

Explanation:

As we know that total power used in the room is given as

$P = P_1 + P_2 + P_3 + P_4$

here we have

$P_1 = (110)(3) = 330 W$

$P_2 = 100 W$

$P_3 = 60 W$

$P_4 = 3 W$

$P = 330 + 100 + 60 + 3$

$P = 493 W$

Part a)

Since power supply is at 110 Volt so the current obtained from this supply is given as

$110\times i = 493$

$i = 4.48 A$

now resistance of transmission line

$R = \frac{\rho L}{A}$

$R = \frac{(2.8 \times 10^{-8})(10\times 10^3)}{\pi(4.126\times 10^{-3})^2}$

$R = 5.23 \ohm$

now power loss in line is given as

$P = i^2 R$

$P = (4.48)^2(5.23)$

$P = 105 W$

Now percentage loss is given as

$percentage = \frac{loss}{supply} \times 100$

$percentage = \frac{105}{493} \times 100$

$percentage = 21.3$ %

Part b)

now same power must have been supplied from the supply station at 110 kV, so we have

$110 \times 10^3 (i ) = 493$

$i = 4.48\times 10^{-3} A$

now power loss in line is given as

$P = i^2 R$

$P = (4.48 \times 10^{-3})^2(5.23)$

$P = 1.05 \times 10^{-4} W$

Now percentage loss is given as

$percentage = \frac{loss}{supply} \times 100$

$percentage = \frac{1.05 \times 10^{-4}}{493} \times 100$

$percentage = 2.13 \times 10^{-5}$ %

6 0

3 years ago

Please Help!!!<br><br> For A&B

klio [65]

Answer:

A. 40N

B. 5m/s

Explanation:

A.

Impulse is equal to the area under the curve of a force vs. time graph. In this case, the area is in the shape of a triangle with base 8 (12-4=8) and perpendicular height 10:

<em>Area of a triangle = (1/2)bh</em>

A=(1/2)*8*10

=40

ANSWER: 40N

B.

<em>Impulse = mass * velocity</em>

40 = 8v

v = 5

ANSWER: 5m/s

5 0

2 years ago

If something is 50% efficient, how many joules of wasted energy will there be if 750J of energy is put in?

Andreas93 [3]

Answer:

<u><em>375 J</em></u>

Explanation:

<u><em>Total energy</em></u> = 750 J

<u><em>Efficiency</em></u> = 50%

<u><em>Wasted energy</em></u> = 50% [100% - 50%]

<u><em>Amount of wasted energy</em></u>

= 750 x 50%

= 750 x 0.5

= 375 J

7 0

2 years ago

Read 2 more answers

PLEASE HELP ASAP THANK YOU You're out for run. Your initial velocity is 1.5 m/s. Suddenly a crazy dog starts chasing you and you

Cerrena [4.2K]

Answer:

Your displacement would be

s = 22.5 m

s=1/2(v+u)t

5 0

2 years ago

2 kg steel ball is dropped straight down ont a hard horixontal florr and bounces straight up . the balls speed just before and j

Rainbow [258]

Answer:

$40 \frac{kg*m}{s}$

Explanation:

Impulse-momentum theorem states that impulse is equal to the change of momentum:

$\overrightarrow{J}=\overrightarrow{p}_{f}-\overrightarrow{p}_{i}$ (1)

with pf the final momentum and pi the initial momentum. Knowing that momentum is mass (m) times velocity (1) is:

$\overrightarrow{J}=m \overrightarrow{v}_{f}- m \overrightarrow{v}_{i}$

It's important to note that we're dealing with vector quantities so direction matters. If we choose towards the floor positive direction then the initial velocity is positive and the final velocity is negative, so:

$\overrightarrow{J}=-(2kg)(10\frac{m}{s}) - (2.0kg)(10\frac{m}{s})$

$\overrightarrow{J}=-40 \frac{kg*m}{s}$

So, the impulse delivered to the floor is $40 \frac{kg*m}{s}$

5 0

2 years ago