Answer:
Newton's law of cooling states that the rate of heat loss of a body is directly proportional to the difference in the temperatures between the body and its surroundings. The law is frequently qualified to include the condition that the temperature difference is small and the nature of heat transfer mechanism remains the same. As such, it is equivalent to a statement that the heat transfer coefficient, which mediates between heat losses and temperature differences, is a constant. This condition is generally met in heat conduction (where it is guaranteed by Fourier's law) as the thermal conductivity of most materials is only weakly dependent on temperature. In convective heat transfer, Newton's Law is followed for forced air or pumped fluid cooling, where the properties of the fluid do not vary strongly with temperature, but it is only approximately true for buoyancy-driven convection, where the velocity of the flow increases with temperature difference. Finally, in the case of heat transfer by thermal radiation, Newton's law of cooling holds only for very small temperature differences.
When stated in terms of temperature differences, Newton's law (with several further simplifying assumptions, such as a low Biot number and a temperature-independent heat capacity) results in a simple differential equation expressing temperature-difference as a function of time. The solution to that equation describes an exponential decrease of temperature-difference over time. This characteristic decay of the temperature-difference is also associated with Newton's law of cooling
Explanation :
Takumi wears sunscreen and a hat each time he works in the yard. This is to protect himself with the strong radiation coming from the sun. UV rays that are coming from the sun are the main cause of skin cancer.
Stochastic effects are the effects that are caused by chance. Cancer is one of the main stochastic effects.
So, the correct option is (b) "the severity of stochastic effects, such as cancer".
Answer:
-8.4°C
Explanation:
From the principle of heat capacity.
The heat sustain by an object is given as;
H = m× c× (T2-T1)
Where H is heat transferred
m is mass of substance
T2-T1 is the temperature change from starting to final temperature T2.
c- is the specific heat capacity of ice .
Note : specific heat capacity is an intrinsic capacity of a substance which is the energy substained on a unit mass of a substance on a unit temperature change.
Hence ; 35= 1× c× ( T2-(-25))
35= c× ( T2+25)
35 =2.108×( T2+25)
( T2+25)= 35/2.108= 16.60°{ approximated to 2 decimal place}
T2= 16.60-25= -8.40°C
C, specific heat capacity of ice is =2.108 kJ/kgK{you can google that}
Answer:
induced electromotive force (Voltage) E = - N dΦ / dt
Explanation:
When the magnetic flux this coil induces a current in each turn of the coil, which is why an induced electromotive force (Voltage) appears at the ends of the coil.
This phenomenon is fully explained by Faraday's law
E = - dΦ / dt
where in the case of a coil with N turns of has
E = - N dΦ / dt
Rl flux is the product of the normal to the area by the magnetic field, in this case the flux changes so we can assume that the area of the coil is constant
Answer:
Oxidation
Explanation:
The browning of the apple after you cut it undergoes a natural chemical change called oxidation, wherein the apple's enzymes react with the oxygen in the environment.
