I with this MCQ question pleae

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Exam question 6 with a temperature-time graph of two metal blocks, M and N, heated by identical heaters. Temp/°C axis from 0 to 80 and time/min axis up to 10, with answer options A 1:4, B 1:2, C 2:1, D 4:1.
Hello! I need help with this question. The answer is D but I don't understand why :/ Thanks!
 
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Please post your attempt .

Hint : What is formula for ΔQ ? What is power provided ?
 
Handwritten working on lined paper, rotated: ΔΘ = mcΘ. For block M, Q1 = 1x80xc = 80c; for block N, Q1 = 2x80xc = 160c. Since Q1 is same for both, M/N = 80/160, M/N = 1/2, giving M:N = 1:2.
Hello, Thanks for replying!
 
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  • Handwritten working on lined paper, rotated: ΔΘ = mcΘ. For block M, Q1 = 1x80 x c = 80c; for block N, Q2 = 2x80 x c = 160c. Since Q1 is same for both, M/N = 80/160, M/N = 1/2, so M:N = 1:2.
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Why is Q1 = Q2 ?

Heaters are identical , and so power provided by them will be the same . The heat absorbed by the objects in some time ' t ' will depend on their own properties . It will not necessarily be the same for both .
Try again .

Hope this helps .
 
Oh Yes.. I read the question wrongly. I thought amount of energy provided is the same.

So, if I am not wrong, the gradient of the graph is the specific heat capacity and since mass of N is 2 times the mass of M, in this case, I can just take the mass of N to be 2kg while the mass of M to be 1kg right? (For me to be able to calculate)

I find the gradient of N and divide it by 2 as heat capacity is per kg.Then I have to compare with the gradient of M and derive the ratio.. Am I right?
 
ΔQ = m*c*ΔT ,
∴ P = ΔQ / ΔT = ?

Shiv Narayanan said:
So, if I am not wrong, the gradient of the graph is the specific heat capacity and since mass of N is 2 times the mass of M, in this case, I can just take the mass of N to be 2kg while the mass of M to be 1kg right? (For me to be able to calculate)
No , I think it looks more like ( ΔT / Δt ) .
And no , you can't assume the masses as so . Use P1 / P2 ratio .
 
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