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3 years ago

The voltage between two points in a circuit is 4.2 V. If the resistance between

Physics

2 answers:

Juli2301 [7.4K]3 years ago

6 0

Answer:

A. 0.058 A

Explanation:

viva [34]3 years ago

3 0

Answer:

I = 0.058 [A]

Explanation:

Ohm's law is defined as voltage equal to the product of current by resistance.

$V =I*R$

where:

V = voltage = 4.2 [V]

I = current [amp]

R = resistivity = 72 [ohm]

Now clearing I, we have:

$I = V/R\\I = 4.2/72\\I = 0.058 [A]$

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Both Newton's Law of Universal Gravitation and Coulomb's Law follow the ...

Romashka [77]

Answer:

inverse square relationship

Explanation:

Both the Newton's law of universal gravitation and coulomb's law have their force inversely proportion to the square of the distance between the bodies.

8 0

2 years ago

the ratio of the energy per second radiated by the filament of a lamp at 250k to that radiated at 2000k, assuming the filament i

Naily [24]

Answer:

(a) $\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}$

(b) P = 0.816 Watt

Explanation:

(a)

The power radiated from a black body is given by Stefan Boltzman Law:

$P = \sigma AT^4$

where,

P = Energy Radiated per Second = ?

σ = stefan boltzman constant = 5.67 x 10⁻⁸ W/m².K⁴

T = Absolute Temperature

So the ratio of power at 250 K to the power at 2000 K is given as:

$\frac{P_{250k}}{P_{2000k}}=\frac{\sigma A(250)^4}{\sigma A(2000)^4}\\\\\frac{P_{250k}}{P_{2000k}}=2.4\ x\ 10^{-4}$

(b)

Now, for 90% radiator blackbody at 2000 K:

$P = (0.9)(5.67\ x\ 10^{-8}\ W/m^2.K^4)(1\ x\ 10^{-6}\ m^2)(2000\ K)^4$

P = 0.816 Watt

7 0

3 years ago

A parachutist of mass 56.0 kg jumps out of a balloon at a height of 1400 m and lands on the ground with a speed of 5.10 m/s. How

Vlad [161]

Answer:

769,048.28Joules

Explanation:

A parachutist of mass 56.0 kg jumps out of a balloon at a height of 1400 m and lands on the ground with a speed of 5.10 m/s. How much energy was lost to air friction during this bump

The energy lost due to friction is expressed using the formula;

Energy lost = Potential Energy + Kinetic Energy

Energy lost = mgh + 1/2mv²

m is the mass

g is the acceleration due to gravity

h is the height

v is the speed

Substitute the given values into the formula;

Energy lost = 56(9.8)(1400) + 1/2(56)(5.10)²

Energy lost = 768,320 + 728.28

Energy lost = 769,048.28Joules

Hence the amount of energy that was lost to air friction during this jump is 769,048.28Joules

6 0

3 years ago

How much heat is released as a 5.89 kg block of aluminum cools from 462 °C to 315 °C. The specific heat capacity of aluminum is

aliina [53]

779,247 J is the amount of heat released.

Explanation:

The equation that gives the amount of heat supplied is

$E \text { or } Q=m \times c_{A l} \times \Delta T$

Where,

E or Q – amount of heat supplied

m- mass

$c_{A l}$ - specific heat capacity of Aluminium

$\Delta T$ – temperature variation caused by heat change

The amount of heat energies that causes the temperature to vary $1^{\circ} \mathrm{C}$ or 1 K per kg of the material is known as specific heat capacity (c)

Here, Given data:

$c_{A l}$ – 0.900 J/g.K

To convert gram into kilogram, multiply and divide by $10^{3}$ , we get

Specific heat capacity of aluminum = 900 J/kg. K

m – 5.89 kg

$\Delta T=462^{\circ}-315^{\circ}=147^{\circ} \mathrm{C}$

By substituting the known values in the above equation, we get

$E \text { or } Q=5.89 \times 900 \times 147=779,247 \mathrm{J}$

5 0

3 years ago

Read 2 more answers

A piston–cylinder device initially contains 0.6 m3 of saturated water vapor at 250 kPa. At this state, the piston is resting on

AysviL [449]

Answer:

T2 = 662°c Q(in) = 911kj W(out) = 180kj

Explanation:

1. Firstly, we find the mass from the initial volume and specific volume from steam table A-5 for given pressure and state.

M = V(1)/a(1) = 0.6/0.7183(kg)

Where a(1) = specific volume

M = 0.835kg

The work is determined from the final pressure and the volume change that occurs when it is reached.

W = P2(V2 - V1)

W = P2V2

= 300×0.6kg = 180kg

Therefore, to get the final temperature and final pressure, the final temperature is determined fro steam table A-6 using interpolation.

T2 = T1* + T2*-T1*/a2*-a1* (a2-a1*)

T2 = 600 + 700-600/1.4958-1.34139 (1.43746-1.34139)

T2 = 662°c

2. The final internal energy can be determined in the same way just like the initial ones were done. From A-5 on steam table given the pressure

The heat Q(in) = ∆u + W(out)

= m(U2-U1) + W(out)

= 0.835(3412.3-2536.8)kj

+ 180

Q(in) = 911kj

6 0

3 years ago