a 0.5 m^2 solar collector radiation from the sun and focuses it on 250g of water that is inially at 23 degrees . the average intensity of radiation arriving from the sun at this location is 550 Wm^-2. if you assume that this is collected with 100% efficiency. how much time is required for the collector to raise this temperatuer to boiling, at 100 degrees

Are you taking a test?

lol, no me and my friends how homework and we all ( 5 of us) don't get this question. !!

figure the heat from the sun:

intensity*area*time

set that equal to masswater*specificheatwater*changeinTemp.

Five friends? This is a an easy question, get new smarter friends.

haha, your just too smart =)

thanx

To determine the time required for the collector to raise the temperature of the water to boiling, we can use the heat equation:

Q = mcΔT

where:
Q is the heat transferred to the water (in Joules)
m is the mass of water (in kg)
c is the specific heat capacity of water (approximately 4186 J/kg°C)
ΔT is the temperature change (in °C)

First, let's calculate the heat required to raise the temperature of the water from 23°C to 100°C:

Q = (m)(c)(ΔT)
Q = (0.25 kg)(4186 J/kg°C)(100°C - 23°C)
Q = (0.25 kg)(4186 J/kg°C)(77°C)
Q = 808,465 J

Next, we need to determine the amount of energy collected by the solar collector, taking into account the efficiency. The efficiency is stated as 100%, which means all the radiation is collected:

Energy collected = (Area)(Intensity)
Energy collected = (0.5 m^2)(550 W/m^2)
Energy collected = 275 J

Since 100% of the radiation energy is collected and converted into heat energy, the energy collected by the solar collector is equal to the heat transferred to the water:

Q = Energy collected
808,465 J = 275 J

Finally, we can calculate the time required for the collector to raise the temperature of the water to boiling:

Time = Q / Power
Time = (808,465 J) / (275 W)
Time ≈ 2,939 seconds (rounded to the nearest second)

Therefore, it would take approximately 2,939 seconds (or 48.98 minutes) for the collector to raise the temperature of the water to boiling (100°C).