<h3>Answer</h3>
(A) Resistance is directly related to length.
<h3>Explanation</h3>
Formula for resistance
R = p(length) / A
where R = resistance
p = resistivity(material of wire)
A = cross sectional area
So it can be seen that resistance depends upon 3 factors that are length of wire , resistivity of wire and the cross sectional area of the wire.
If two of the factors, resistivity and cross sectional area, are kept constant then the resistance is directly proportional to the length of wire.
<h3> R ∝ length</h3>
This means that the resistance of the wire increases with the increase in length of the wire and decreases with the decrease of length of the wire.
If it produces 20J of light energy in a second, then that 20J is the 10% of the supply that becomes useful output.
20 J/s = 10% of Supply
20 J/s = (0.1) x (Supply)
Divide each side by 0.1:
Supply = (20 J/s) / (0.1)
<em>Supply = 200 J/s </em>(200 watts)
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Here's something to think about: What could you do to make the lamp more efficient ? Answer: Use it for a heater !
If you use it for a heater, then the HEAT is the 'useful' part, and the light is the part that you really don't care about. Suddenly ... bada-boom ... the lamp is 90% efficient !
Answer: <em>An object at rest remains at rest, or if in motion, remains in motion at a constant velocity unless acted on by a net external force.</em>
Explanation: meaning, an object will continue in its same direction until stopped or acted upon by another force.
The unseen force of gravity acts on the sled,
accelerating it downward.
The mass of the cold water, given the data from the question is 500 g
<h3>Data obtained from the question</h3>
- Mass of warm water (Mᵥᵥ) = 200 g
- Temperature warm water (Tᵥᵥ) = 75 °C
- Temperature of cold water (T꜀) = 5 °C
- Equilibrium temperature (Tₑ) = 25 °C
- Specific heat capacity of the water = 4.184 J/gºC
- Mass of cold water (M꜀) =?
<h3>How to determine the mass of the cold water </h3>
Heat loss = Heat gain
MᵥᵥC(Tᵥᵥ – Tₑ) = M꜀C(Tₑ – T꜀)
200 × 4.184 (75 – 25) = M꜀ × 4.184(25 – 5)
41840 = M꜀ × 83.68
Divide both side 83.68
M꜀ = 41840 / 83.68
M꜀ = 500 g
Learn more about heat transfer:
brainly.com/question/6363778
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