The answer is "A" Endothermic. Hope that helped :)
Answer:
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Answer:
E. two times the original diameter
Explanation:
Resistance of a wire is:
R = ρ L/A
where ρ is the resistivity of the material, L is the length, and A is the cross-sectional area.
For a round wire with diameter d:
R = ρ L / (¼ π d²)
The two wires must have the same resistance, so:
ρ₁ L₁ / (¼ π d₁²) = ρ₂ L₂ / (¼ π d₂²)
The wires are made of the same material, so ρ₁ = ρ₂:
L₁ / (¼ π d₁²) = L₂ / (¼ π d₂²)
The new length is four times the old, so 4 L₁ = L₂:
L₁ / (¼ π d₁²) = 4 L₁ / (¼ π d₂²)
1 / (¼ π d₁²) = 4 / (¼ π d₂²)
Solving:
1 / (d₁²) = 4 / (d₂²)
(d₂²) / (d₁²) = 4
(d₂ / d₁)² = 4
d₂ / d₁ = 2
So the new wire must have a diameter twice as large as the old wire.
Answer:
Explanation:
Current in a wire is 120mA
I = 120mA = 120 × 10^-3 A
I = 0.12 A
If the voltage applied at across the wire is tripled
From ohms law
V=IR
R = V / I
Since R is constant
Then,
V / I = K
Then, we can say
V / I = V' / I'
Given that,
Initially
V = V and I = 120mA
Then, V' = 3V and I' =?
So,
V / I = V' / I'
V / 120 = 3V / I'
Cross multiply
V × I' = 120 × 3V
Divide both sides by V
I' = 120 × 3V / V
I' = 360mA
So, the current in the wire when the voltage was tripled is 360mA, the current was also tripled
Materials that conduct heat and electricity well in the solid state result when metals bond with metals. <span>This type of bonding is called metallic bonding. Metallic bonding is when positive ions (metals) are in a 'sea of negative electrons'. The electrons are delocalised, which means they can move around easily and carry charge, and this enables it to conduct electricity, even in a solid state.</span>
