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3 years ago

Which of the following would decrease the resistance to the flow of an electric current through a body?

1 answer:

8 0

Shortening the conductor (B) would decrease the resistance
to the flow of an electric current through a body.

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A straight fin is made from copper (k = 388 W/m-K) and is 0.5 cm in diameter and 30 cm long. The temperature at the base of the

erastovalidia [21]

Answer:

The rate of transfer of heat is 0.119 W

Solution:

As per the question:

Diameter of the fin, D = 0.5 cm = 0.005 m

Length of the fin, l =30 cm = 0.3 m

Base temperature, $T_{b} = 75^{\circ}C$

Air temperature, $T_{infty} = 20^{\circ}$

k = 388 W/mK

h = $20\ W/m^{2}K$

Now,

Perimeter of the fin, p = $\pi D = 0.005\pi \ m$

Cross-sectional area of the fin, A = $\frac{\pi}{4}D^{2}$

A = $\frac{\pi}{4}(0.5\times 10^{-2})^{2} = 6.25\times 10^{- 6}\pi \ m^{2}$

To calculate the heat transfer rate:

$Q_{f} = \sqrt{hkpA}tanh(ml)(T_{b} - T_{infty})$

where

$m = \sqrt{\frac{hp}{kA}} = \sqrt{\frac{20\times 0.005\pi}{388\times 6.25\times 10^{- 6}\pi}} = 41.237$

Now,

$Q_{f} = \sqrt{20\times 388\times 0.005\pi\times 6.25\times 10^{- 6}\pi}tanh(41.237\times 0.3)(75 - 20) = 0.119\ W$

5 0

3 years ago

An air conditioner has a power rating of 3000 W and is used daily. Its electrical

Anarel [89]

Answer:

5.714 hours / day

Explanation:

Calculate the hours used in that week

120000 / 3000 = 120 / 3 = 40 hours a week

Calculate the amount it is used in one day

40 / 7 = 5.71428571 hours or 5.714 hours/day

5 0

2 years ago

Read 2 more answers

Consider this row in the periodic table of elements. Which element(s) are most likely to conduct electricity?

Sidana [21]

A) lithium and beryllium

Explanation:

From the given row on the periodic table, only lithium and beryllium will conduct electricity.

What makes a substance able to conduct electricity?

The presence of free mobile electrons and in some, ions allows them to carry electric currents.

Metals are generally known to be good conductors of heat and electricity. This is because, metals have a large pool of electrons i.e free mobile electrons. They are electropositive with a large size and readily release their electrons for conduction.

Lithium and Beryllium are in the metallic block on the periodic table.

Learn more:

Metals brainly.com/question/2474874

#learnwithBrainly

6 0

3 years ago

Read 2 more answers

Answer them all please!!

liubo4ka [24]

Answer:

1. stomach

2. arteries