<u>Answer:</u>
<em>A water strider can walk along the surface of earth due to the surface tension of water.
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<u>Explanation:</u>
Fluids have a <em>tendency to shrink to minimum possible surface area</em> and this is called surface tension. It usually occurs due to the greater force of cohesion between molecules of same substance when compared to adhesive force between molecules of different substances. Objects with greater densities can float along water surface due to the <em>role played by surface tension.
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When insects walk along the water surface they are pulled down due to gravity. But the force of attraction between the legs of the insect and water molecules is minimal. Thus the surface tension would always tend to maintain the <em>flatness of water overcoming</em> the push by the legs of the strider.
When the insect’s weight pulls it down , the surface tension pushes it upwards overcoming this force of gravity. This is how<em> water striders move along the surface of water. </em>
Answer:
λ = 1.4 × 10^(-7) m
Explanation:
We are given;
distance of eye piece from the source;D = 1.5 m
distance between the virtual sources;d = 7.5 × 10^(-4) m
To find the wavelength, we will use the formula for fringe width;
X = λD/d
Where X is fringe width, λ is wavelength, while d and D remain as before.
Now, fringe width = eye-piece distance moved transversely/number of fringes
Eye piece distance moved transversely = 1.88 cm = 1.88 × 10^(-2) m
Thus,
Fringe width = (1.88 × 10^(-2))/10 = 1.88 × 10^(-3) m
Thus;
1.88 × 10^(-3) = λ(1.5)/(7.5 × 10^(-4))
λ = [1.88 × 10^(-3) × (7.5 × 10^(-4))]/1.5
λ = 1.4 × 10^(-7) m
The cost of boiling 500 cm³ of water using the 3 KW Kettle is 1.35p
<h3>What is power? </h3>
This is defined as the rate in which energy is consumed. Electrical power is expressed mathematically as:
Power (P) = Energy (E) / time (t)
P = E / t
<h3>How to determine the energy</h3>
- Power (P) = 3 KW
- Time (t) = 3 mins = 3 / 60 = 0.05 h
- Energy (E) =?
E = Pt
E = 3 × 0.05
E = 0.15 KWh
<h3>How to determine the cost</h3>
- Energy (E) = 0.15 KWh
- Cost per unit = 9p
- Cost =?
Cost = Energy × cost per unit
Cost = 0.15 × 9
Cost = 1.35p
Learn more about electrical power:
brainly.com/question/64224
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The Electromagnetic spectrum.
Choice-B is the true one.