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3 years ago

Which of these devices does NOT contain a magnet or electromagnet?

2 answers:

8 0

C. A lightbulb

This is because a light bulb uses a filament to send a current to turns electricity into light. Because filaments are mostly made of tungsten, the resistance of the filament gets so hot that it heats the light bulb.

This process does not need a magnet or electromagnet like the doorbell, electric motor, and telephones need magnets.

Alex_Xolod [135]3 years ago

7 0

A light bulb don’t have magnet

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Charge q1 is distance r from a positive point charge Q. Charge q2=q1/3 is distance 2r from Q. What is the ratio U1/U2 of their p

worty [1.4K]

We have that The ratio U1/U2 of their potential energies due to their interactions with Q is

$U1/U2=6$
$U1/U2=6$

From the question we are told that

Question 1

Charge q1 is distance r from a positive point charge Q.

Question 2

Charge q2=q1/3 is distance 2r from Q.

Charge q1 is distance s from the negative plate of a parallel-plate capacitor.

Charge q2=q1/3 is distance 2s from the negative plate.

Generally the equation for the potential energy is mathematically given as

$U=\frac{-k*qQ}{r}$

Therefore

The Equations of U1 and U2 is

For U1

$U1=\frac{-k*q_1Q}{r}$

For U2

$U2=\frac{-k*q_1Q}{3*2r}$

Since

U is a function of q and q2=q1/3

Therefore

$U1/U2=6$

For Question 2

For U1

$U1=\frac{-k*q_1Q}{s}\\\\For U2\\\\U2=\frac{-k*q_1Q}{3*2r}$

Therefore

$U1/U2=6$

For more information on this visit

brainly.com/question/23379286?referrer=searchResults

7 0

3 years ago

Explain how the formula for the force and the force between charged particles is similar to the formula for the gravitational fo

sashaice [31]

Formula for gravitational force shows it is inversely proportional to the distance between two masses squared this is similar to the electrostatic force thay changes according to the separation squared.
The difference is that gravity is proportional to the product of the two masses. Electro static force is proportional to the product of the two charges.

7 0

3 years ago

1. 412.9 g of dry ice sublimes at room temperature. a. What’s changing? --- sublimation b. What constant will you use? ----- 25.

hoa [83]

1. 236 kJ

a. The phase (or state of matter) of the substance: from solid state to gas state (sublimation)

b. The enthalphy of sublimation, given by: $\lambda=571 J/g$

c. The equation to use will be $Q=m\lambda$ , where m is the mass of dry ice and $\lambda$ is the enthalpy of sublimation

d. The energy is being absorbed, because the heat is transferred from the environment to the dry ice: as a consequence, the bonds between the molecules of dry ice break and then move faster and faster, and so the substance turns from solid into gas directly.

e. The amount of energy being transferred is

$Q=m\lambda=(412.9 g)(571 J/g)=2.36\cdot 10^5 J=236 kJ$

2. 165 kJ

a. The phase (or state of matter) of the substance: from gas state to liquid state (condensation)

b. The latent heat of vaporisation of water, given by $\lambda=2260 J/g$

c. The equation to use will be $Q=m\lambda$ , where m is the mass of steam that condenses and $\lambda$ is the latent heat of vaporisation

d. The energy is being released, since the substance turns from a gas state (where molecules move faster) into liquid state (where molecules move slower), so the internal energy of the substance has decreased, therefore heat has been released

e. The amount of energy being transferred is

$Q=m\lambda=(72.9 g)(2260 J/g)=1.65\cdot 10^5 J=165 kJ$

3. 3.64 kJ

a. Only the temperature of the substance (which is increasing)

b. The specific heat capacity of silver, which is $C_s = 0.240 J/gC$

c. The equation to use will be $Q=m C_s \Delta T$ , where m is the mass of silver, Cs is the specific heat capacity and $\Delta T$ the increase in temperature

d. The energy is being absorbed by the silver, since its temperature increases, this means that its molecules move faster so energy should be provided to the silver by the surroundings

e. The amount of energy being transferred is

$Q=m C_s \Delta T=(39.2 g)(0.240 J/gC)(412.9^{\circ}C-25.9^{\circ}C)=3641=3.64 kJ$

4. 89 kJ

a. Both the phase of the substance (from solid to liquid) and then the temperature

b. The latent heat of fusion of ice: $\lambda=334 J/g$ and the specific heat capacity of water: $C_s=4.186 J/gC$

c. The equation to use will be $Q=m\lambda + m C_s \Delta T$ , where m is the mass of ice, $\lambda$ the latent heat of fusion of ice, Cs is the specific heat capacity of water and $\Delta T$ the increase in temperature

d. The energy is being absorbed by the ice, at first to break the bonds between the molecules of ice and to cause the melting of ice, and then to increase the temperature of the water

e. The amount of energy being transferred is

$Q=m\lambda +m C_s \Delta T=(156.3 g)(334 J/g)+(156.3 g)(4.186 J/gC)(56.232^{\circ}C-0^{\circ}C)=8.9\cdot 10^4 J=89 kJ$