100 W heater is switched on for 5 minutes to melt ice. What is the mass of ice that melts at 0oC? ( The specific latent heat of fusion of ice is 334 J/g).
Correct answer: A. 90 g
- A. 90 g
- B. 90 kg
- C. 1.5 kg
- D. 1.5 g
Explanation
To calculate the mass of ice that melts, we can use the formula:Q = m * Lwhere:Q = heat energy absorbed or released during a phase change (in joules)m = mass of the substance that melts (in grams)L = specific latent heat of fusion (in J/g)Given information:Power of the heater (P) = 100 WTime (t) = 5 minutes = 5 * 60 seconds = 300 secondsSpecific latent heat of fusion of ice (L) = 334 J/gFirst, we need to calculate the total energy supplied by the heater:Energy (Q) = Power (P) * Time (t)Energy (Q) = 100 W * 300 secondsEnergy (Q) = 30,000 joulesNow, we can calculate the mass of ice that melts:m = Q / Lm = 30,000 joules / 334 J/gm ≈ 90 gSo, approximately 90 g of ice will melt when the 100 W heater is switched on for 5 minutes.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? [email protected]
About Thermal Equilibrium and Heat
Thermal equilibrium means that bodies in contact have the same temperature and no net heat flows between them. The topic distinguishes heat from temperature, uses the zeroth law of thermodynamics, and covers heat transfer, specific heat capacity, thermal expansion and the conditions for reaching equilibrium.
Practise Thermodynamics
714 free Thermodynamics MCQs from Physics, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Physics questions like this
Physics is on 16 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Thermal Equilibrium and Heat questions
100 W heater is used to melt 50 g of ice at OC. How long should the heater be switched on? (Specific latent heat of fusion of ice is 334 J/g)
Two spheres are made of the same metal and have the same radius, but one is hollow and the other is solid. The spheres are taken through the same temperature increase. Which sphere expands more?
Equal masses of paraffin wax and water are mixed in a container of negligible thermal capacity. If the initial temperature of water is 80oC and that of wax is 20oC, what is the final temperature of the mixture?
Which of the following is equivalent to a temperature -50oC?
A reversible Carnot engine converts 1/6th of heat into input works. When the temperature of the sink is reduced by 62˚C then the efficiency is doubled. The temperature of the source and sink is:
A 1.0 kW heater supplies energy to a liquid of mass 1 kg. The temperature of the liquid changes by 80 K in a time of 400 s. The specific heat capacity of the liquid is 4.0 kJ / kg*K. What is the average power lost by the liquid?