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3 years ago

Help with these questions please , 15 PTS & brainliest

Physics

1 answer:

myrzilka [38]3 years ago

6 0

For these two questions, first you need to know that the voltage across each branch of a parallel circuit is the same.

So, for Q5, we can first find out the voltage across R₂ by V=IR.

Voltage across R₂ = 2.5 × 8 = 20V

Since R₂ and R₃ are in parallel circuit, their voltage should be the same. Thus, voltage across R₃ is 20V.

So, by V=IR,

current of R₃ = $\frac{20}{4}$ = 5A

Q6. voltage across R₁ = 2 × 4 = 8V

∴voltage across R₂ = 8V

current of R₂ = $\frac{8}{8}$ = 1A

<h3><u>Alternative method</u></h3>

From these two examples, you can find out that the current of each branch of the parallel circuit is inversely proportional to the resistance of the branch.

ie. for Q5,

$\frac{R2}{R3}$ = $\frac{I3}{I2}$

$\frac{8}{4}$ = $\frac{I3}{2.5}$

I₃ = 5A

Q6. $\frac{R1}{R2}$ = $\frac{I2}{I1}$

$\frac{4}{8}$ = $\frac{I2}{2}$

I₂ = 1A

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An inactive teen should eat approximately

Andrej [43]

Answer:

so i believe your answer is abt 1800-2400

Explanation:

According to the Dietary Guidelines for Americans 2010, sedentary teen girls between the ages of 13 and 18 need 1,600 to 1,800 calories per day, while active girls require 2,200 to 2,400 calories each day

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3 years ago

A 1.50 cm high diamond ring is placed 20.0 cm from a concave mirror with radius of curvature 30.00 cm. The magnification is ____

Rama09 [41]

Answer:

Magnification, m = -0.42

Explanation:

It is given that,

Height of diamond ring, h = 1.5 cm

Object distance, u = -20 cm

Radius of curvature of concave mirror, R = 30 cm

Focal length of mirror, f = R/2 = -15 cm (focal length is negative for concave mirror)

Using mirror's formula :

$\dfrac{1}{f}=\dfrac{1}{u}+\dfrac{1}{v}$ , f = focal length of the mirror

$\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}$

$\dfrac{1}{v}=\dfrac{1}{-15}+\dfrac{1}{-20}$

v = -8.57 cm

The magnification of a mirror is given by,

$m=\dfrac{-v}{u}$

$m=\dfrac{-(-8.57)}{-20}$

m = -0.42

So, the magnification of the concave mirror is 0.42. Thew negative sign shows that the image is inverted.

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4 years ago

Which sentence uses the correct adverb to make a comparison?

Arturiano [62]

Option C would be the right one

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3 years ago

Which of the following statements is consistent with Thomson’s and Millikan’s work with cathode rays and electrons? (A) Cathode

victus00 [196]

Answer:

Dalton's ideas proved foundational to modern atomic theory. However, one of his underlying assumptions was later shown to be incorrect. Dalton thought that atoms were the smallest units of matter-−minustiny, hard spheres that could not be broken down any further. This assumption persisted until experiments in physics showed that the atom was composed of even smaller particles. In this article, we will discuss some of the key experiments that led to the discovery of the electron and the nucleus.

J.J. Thomson and the discovery of the electron

In the late 19^{\text{th}}19

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A diagram of a cathode ray tube.

A diagram of J.J. Thomson's cathode ray tube. The ray originates at the cathode and passes through a slit in the anode. The cathode ray is deflected away from the negatively-charged electric plate, and towards the positively-charged electric plate. The amount by which the ray was deflected by a magnetic field helped Thomson determine the mass-to-charge ratio of the particles. Image from Openstax, CC BY 4.0.

To test the properties of the particles, Thomson placed two oppositely-charged electric plates around the cathode ray. The cathode ray was deflected away from the negatively-charged electric plate and towards the positively-charged plate. This indicated that the cathode ray was composed of negatively-charged particles.

Thomson also placed two magnets on either side of the tube, and obser

Explanation:

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3 years ago

Part B - Permeability of the lipid bilayer Some solutes are able to pass directly through the lipid bilayer of a plasma membrane

Helen [10]

This Question is not complete

Complete Question:

Part B - Permeability of the lipid bilayer Some solutes are able to pass directly through the lipid bilayer of a plasma membrane, whereas other solutes require a transport protein or other mechanism to cross between the inside and the outside of a cell. The fact that the plasma membrane is permeable to some solutes but not others is what is referred to as selective permeability. Which of the following molecules can cross the lipid bilayer of a membrane directly, without a transport protein or other mechanism?

a) proteins

b) water

c) ions

d) sucrose

e) lipids

f) carbon dioxide

g) oxygen

Answer:

b) water

e) lipids

f) carbon dioxide

g) oxygen

Explanation:

Diffusion is the means by which molecules like water, lipids, carbon dioxide and oxygen easily move across the lipid bilayer of a membrane directly without the use of a transport protein or any another mechanism.

Diffusion is the way or means through which molecules( such as gases or liquids) move across a membrane from and region of higher concentration to a region of lower concentration.

Before a molecule can pass through the semi permeable membrane without the use of any mechanism or transport protein, it has to be:

a) a small molecule

b) an uncharged molecule

c) an hydrophobic molecule

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3 years ago