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MakcuM [25]
3 years ago
13

When determining whether a chemical reaction has taken place, you observe and look for several indicators. Which would be consid

ered an indication that a chemical reaction or chemical change has taken place? A) Solid melts. B) Heat is given off. C) Substance dissolves D) Substance changes shape.
Physics
1 answer:
Inga [223]3 years ago
6 0
The answer is B.

A cannot be the answer is melting is a physical change. No chemical reaction took place.

B is the answer as it is a EXOTHERMIC REACTION so heat will be given off.

C cannot be the answer as dissolving is basically atoms becoming ions, not a chemical reaction whereby a reactant reacts with another reactant to form a product.

D cannot be the answer. Same reason as for why A is not the answer.

Cheers.
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the answers are A, B, C, E  HOPED THIS HELPED

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What is the maximum value of the magnetic field at a distance of 2.5 m from a light bulb that radiates 100 W of single-frequency
Anvisha [2.4K]

Answer:

1.04\times 10^{-7} T

Explanation:

IP  = Power of the bulb = 100 W

r  = distance from the bulb = 2.5 m

I = Intensity of light at the location

Intensity of the light at the location is given as

I = \frac{P}{4\pi r^{2}}

I = \frac{100}{4(3.14) (2.5)^{2}}

I = 1.28 W/m²

B_{o} = maximum magnetic field

Intensity is given as

I = \frac{B_{o}^{2}c}{2\mu _{o}}

1.28 = \frac{B_{o}^{2}(3\times 10^{8})}{2(12.56\times 10^{-7})}

B_{o} = 1.04\times 10^{-7} T

7 0
3 years ago
A ball is thrown at 20 m/s from the ground upwards at an angle of elevation of 30°. How far away does it land? 35.35 m
mestny [16]

Answer:

35.35 m

Explanation:

The following data were obtained from the question:

Initial velocity (u) = 20 m/s

Angle of projection (θ) = 30°

Acceleration due to gravity (g) = 9.8 m/s²

Range (R) =.?

The range (i.e how far away) of the ball can be obtained as follow:

R = u² Sine 2θ /g

R = 20² Sine (2×30) / 9.8

R = 400 Sine 60 / 9.8

R = (400 × 0866) / 9.8

R = 346.4 / 9.8

R = 35.35 m

Therefore, the range (i.e how far away) of the ball is 35.35 m

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3 years ago
I am pushing in a large box with 200 N of force. Clint is pushing on the box with 200 N of force in the opposite direction. Why
andreev551 [17]

Answer:

Balanced forces

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Balanced forces are where two forces of equal size act on an object in opposite directions. It means that in each direction, any pushes and pulls are balanced by another force in the opposite direction.

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What are the advantages and disadvantages of renewable and non-renewable energy?
bogdanovich [222]

Renewable energy

<u>Advantages :-</u>

1. Easily regenerate

2. Boost economic growth

3. Easily available

4. Support environment

5. Low maintenance cost

<u>Disadvantages :-</u>

1. Weather dependency

2. High installation cost

3. Noise caused by wind energy

4. Fluctuation problem (solar)

5. Intermittency issue (wind)

Non-renewable energy

<u>Advantages :-</u>

1. Concentrated energy source

2. Reliable energy source

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<em>I hope this helps.....</em>

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