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irga5000 [103]
3 years ago
8

How many protons are in Calcium? (* Hint: The Atomic number of Calcium is 20).

Physics
1 answer:
ryzh [129]3 years ago
3 0

Answer:

The answer to your question is: 20

Explanation:

Atomic number is the number of proton and atom has. Each element has a specific number of protons, if the number of protons change, then this is a new element.

Mass number is the number of protons and neutrons and atom has.

                       Mass number = protons + neutrons

Data

Number of protons = ?

Atomic number = 20

Then,

           atomic number = number of protons = 20

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When you convet km to miles this is what you get 

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3 years ago
Q 2 Two mirrors meet at right angles. A ray of light is incident on one at an angle of 30°
serg [7]

a ray of light is incident towards a plane mirror at an angles of 30degrees with the mirror surface. what will be the angles of reflection is 60degree.

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3 years ago
How does the current in a circuit change if the resistance is doubled? The current is halved. The current is doubled. The curren
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Answer:

The current is halved

Explanation:

The relationship between the current and the resistance is given by Ohm's Law, as follows:

V = IR\\I = \frac{V}{R}

where,

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I = Current

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Therefore, if we double the resistance:

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Hence the correct option is:

<u>The current is halved</u>

7 0
3 years ago
Read 2 more answers
You overhear two students discussing the topic of Doppler shift.
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Answer:

agree with student 2, disagree with student 1

Explanation:

If you want to know if the wavelength of light was shifted you have to know the original wavelengths

Since we know the absorption spectrum for elements like hydrogen, we can look for these absorption lines in the star's spectra and figure out what direction these lines are shifted and tell if the star is moving away or towards us

The color of the star refers to the temperature of the star's surface which is not related to the doppler shift of the star

5 0
3 years ago
slader How much energy is required to move a 1040 kg object from the Earth's surface to an altitude four times the Earth's radiu
andrew-mc [135]

Answer:

ΔU = 5.21 × 10^(10) J

Explanation:

We are given;

Mass of object; m = 1040 kg

To solve this, we will use the formula for potential energy which is;

U = -GMm/r

But we are told we want to move the object from the Earth's surface to an altitude four times the Earth's radius.

Thus;

ΔU = -GMm((1/r_f) - (1/r_i))

Where;

M is mass of earth = 5.98 × 10^(24) kg

r_f is final radius

r_i is initial radius

G is gravitational constant = 6.67 × 10^(-11) N.m²/kg²

Since, it's moving to altitude four times the Earth's radius, it means that;

r_i = R_e

r_f = R_e + 4R_e = 5R_e

Where R_e is radius of earth = 6371 × 10³ m

Thus;

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× 1040((1/(5 × 6371 × 10³)) - (1/(6371 × 10³))

ΔU = 5.21 × 10^(10) J

7 0
3 years ago
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