wiz-icon
MyQuestionIcon
MyQuestionIcon
1
You visited us 1 times! Enjoying our articles? Unlock Full Access!
Question

An object of mass 8 kg falls through a height of 60 m and by means of a mechanical linkage, rotates a paddle wheel that stirs 0.8 kg of water. Determine the change in temperature of water if initial temperature was 15C. Assume no heat is lost to surroundings, specific heat of water, c=4190 J/kgC).

A
0.5C
No worries! We‘ve got your back. Try BYJU‘S free classes today!
B
1.4C
Right on! Give the BNAT exam to get a 100% scholarship for BYJUS courses
C
2.1C
No worries! We‘ve got your back. Try BYJU‘S free classes today!
D
3.6C
No worries! We‘ve got your back. Try BYJU‘S free classes today!
Open in App
Solution

The correct option is B 1.4C
Given that
Mass of object (m)=8 kg
Height of fall (h)=60 m
Mass of water (mw)=0.8 kg
Initial temperature Ti=15C
Loss of mechanical energy E=mgh
Change in temperature of water =ΔT
Thermal energy gained by water E=mwcΔT

From law of conservation of energy,
mwcΔT=mgh
ΔT=mghmwc
ΔT=8 kg×9.8 m/s2×60 m0.8 kg×(4190 J/kgC)
Δ T=1.4C
Hence, the answer (b) is correct.

flag
Suggest Corrections
thumbs-up
0
Join BYJU'S Learning Program
Join BYJU'S Learning Program
CrossIcon