Answer:
energy can exist in many different forms
Explanation:
Let's start with an infinitive: it has a form "to..." - only sentences C and D have a phrase like this, so we can exclude other options.
Among those, C does not have a gerund, which is a verbal form: "dreaming" has a function of a noun there.
So the correct answer is the remaining one, D.
From tables, the speed of sound at 0°C is approximately
V₁ = 331 m/s (in air)
V₃ = 5130 m/s (in iron)
Distance traveled is
d = 100 km = 10⁵ m
Time required to travel in air is
t₁ = d/V₁ = 10⁵/331 = 302.12 s
Time required to travel in iron is
t₂ = d/V₂ = 10⁵/5130 = 19.49 s
The difference in time is
302.12 - 19.49 = 282.63 s
Answer: 283 s (nearest second)
The correct answer is
<span>A. decreasing the current
In fact, the magnetic field produced by a current carrying wire is given by
</span>

<span>where
</span>

is the vacuum permeability
<span>I is the current in the wire
r is the distance from the wire at which the field is calculated
We see from the formula that the intensity of the field, B, is directly proportional to the current I, so if the current decreases, the magnetic field strength B decreases as well.</span>