有關「比熱容量」 (in graph)

比熱容低=用少量energy已經可以將1kg物件升好多溫度,假如有樣野比熱容係100,佢只需要100J就已經可以升1度。
比熱容高=用大量energy只能將1kg物件升好少溫度,例如水的比熱容是4200,
即係要成4200J先升得果1度。

所以要知道邊個有最低比熱容就睇slope,最斜果個一定最快。
因為可以係最短時間升到最高溫度=比熱容最低,
而Q可以係咁短時間升到咁高溫度,
而A咁耐先升左果少少。
所以cA>cX>cQ

亦可以咁諗,寫c=E/mT(from E=mcT)
若E係一樣(以Q加熱的時間作準,因為用同樣heater,加熱的能量是一樣),
T越大,c就越細
T越細,c就越大
因為溫度改變最大係Q,最小係A
所以cA>cX>cQ

In a simply wording, the larger specific heat capacity mean harder to heat up.

Take an example, there is 1 kg substance A and B with heat capacity 1000 and 2000 J/kg degree C respectively. If we input 2000J to them, A will increase 2000/1000=2 degree C and B will increase 2000/2000 = 1 degree C.

In your graph, the slope of Q > x > A, for the same input energy, that is it is easier to heat up Q than x and A. That mean the specific heat capacity of Q is the smallest, A is the largest.