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netineya [11]
3 years ago
12

PLEASE HELP!!!

Physics
2 answers:
nasty-shy [4]3 years ago
4 0

(A) The thermal conductors don't have to be hot to transfer heat, as when the case of ice cube is taken, when the ice cube is placed in the warm water, it melts because the thermal heat from the warm water move into the ice cube, the thermal energy of the ice cube increases whereas the thermal energy of the water decreases.

(B) A heat transfer medium is may be presented in the solid, liquid or the vapor phase. It is used to transfer heat from one place to another or to store heat in a reversible form.

(C) Option A is correct.

This is because, the magnetic field lines transfer from North Pole to South pole which is the correct origination and the destination respectively.

Option B is not correct because the magnetic field lines originate from  North Pole but does not end at the South Pole.

Option C is not correct because the magnetic field lines cannot travel from the same pole to the another same pole of the magnet. In this, the magnetic field lines originate from the South  Pole and ends at the South pole of the other magnet which is not possible.

(D) The law of conservation of energy states that energy can neither be created nor destroyed, it can only be transformed from one form to another.  A heat pump is a device  that can pump thermal energy either into (heating) or out of (cooling) an enclosed space, which means system remains the same but the heat gets converted from one form to the another.


fgiga [73]3 years ago
4 0
The answers are as follows: 
21. A situation where an ice cube will transfer heat to an object that it is in contact with is the is the situation where you put an ice cube inside a warm drink. The ice cube that you put inside the warm drink will melt because, thermal heat from the drink moves into the ice cube; the drink thermal energy decreases while the ice cube thermal energy increases.
22. A medium of heat transfer refers to a substance, which acts as agent in a heat exchanger, through which heat is exchanged from one point to the other. The heat medium may be a liquid or a solid. 
31. The picture is option A is true. This is because, the magnetic field lines start from the correct origin, that is, from the north pole and they end in the south pole.
The picture in option B is not correct because, the magnetic field lines from outside the magnet start form the north pole. The magnetic field lines ought to start from the south pole and end in the north pole, not the other way round.
The picture in option C is incorrect because, magnetic field lines can not travel from a like pole to another like pole. The magnetic lines in this picture travel from the south pole to the south pole, which is not possible, because in physics, like do not attract like.
32. The law of conservation of energy states that energy can neither be created nor destroyed, it can only be transformed from one form to another.
A heat pump transfer heat from a cold area to a warm area. The energy that circulates in the heat pump system remains the same, but it is converted from one form to another form.
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A car battery with a 12 V emf and an internal resistance of 0.11 Ω is being charged with a current of 56 A. What are (a) the pot
denpristay [2]

Answer:

Part a)

V = 18.16 V

Part b)

P_r = 345 Watt

Part c)

P = 672 Watt

Part d)

V = 5.84 V

Part e)

P_r = 345 Watt

Explanation:

Part a)

When battery is in charging mode

then the potential difference at the terminal of the cell is more than its EMF and it is given as

\Delta V = E + i r

here we have

E = 12 V

i = 56 A

r = 0.11

now we have

\Delta V = 12 + (0.11)(56) = 18.16 V

Part b)

Rate of energy dissipation inside the battery is the energy across internal resistance

so it is given as

P_r = i^2 r

P_r = 56^2 (0.11)

P_r = 345 W

Part c)

Rate of energy conversion into EMF is given as

P_{emf} = i E

P_{emf} = (56)(12)

P_{emf} = 672 Watt

Now battery is giving current to other circuit so now it is discharging

now we have

Part d)

V = E - i r

V = 12 - (56)(0.11)

V = 12 - 6.16 = 5.84 V

Part e)

now the rate of energy dissipation is given as

P_r = i^2 r

P_r = 56^2 (0.11)

P_r = 345 W

7 0
3 years ago
The children at the local park think the slide is too slow. There is too much fiction. What could you do to decrease the amount
igor_vitrenko [27]
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7 0
3 years ago
What is one common product that uses microwaves
AVprozaik [17]
Electromagnet Radiation
7 0
3 years ago
An electric current in a metal consists of moving
Alik [6]
The answer would be (A) Protons
6 0
3 years ago
Two facing surfaces of two large parallel conducting plates separated by 8.5 cm have uniform surface charge densities such that
elena-s [515]

Answer:

positive plate

E = 5.764 KV / m

W = 490eV or 7.85 * 10^-17 J

E_p = 4.74 *10^(-12) eV

E_k = 490 eV

Explanation:

part a

The potential difference between two plates = 490 V

Distance between two plates = 8.5 cm

Answer: The positive plate is at higher potential because of convention.

part b

Electric Field between the plates

E = V / d

E = 490 / 0.085 = 5.764 KV / m

Answer: Electric Field between the plates E = 5.764 KV / m

part c

Work done by electric field

W = V*q

W = 490 * 1.602*10^-19

W = 7.85 * 10^-17 J

or W = 490 eV

Answer: Work done by electric field W = 490eV or 7.85 * 10^-17 J

part d

Potential Energy of an electron gained:

E_p = m_e * g * d / (1.602*10^-19)

E_p =  9.109*10^-31* 9.81 * 0.085 / (1.602*10^-19)

E_p = 4.74 *10^(-12) eV

Very very small E_p approximately 0

Answer: Potential Energy of an electron gained E_p = 4.74 *10^(-12) eV or 0.

part e

Kinetic Energy of an electron gained:

W - E_p = E_k

E_k = 490eV - 4.74*10^(-12)eV

E_k = 490 eV

Answer: Kinetic Energy of an electron gained E_k = 490 eV

7 0
3 years ago
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