Note: <em>The question states the time to go upstream is a number of times (not explicitly written) the time to go downstream. We'll assume a general number N</em>
Answer:

Explanation:
<u>Relative Speed</u>
If a boat is going upstream against the water current, the true speed of motion is
, being
the speed of the boat and
the speed of the water. If the boat is going downstream, the true speed becomes
.
The question states the time to go upstream is a number of times N (not explicitly written) the time to go downstream. The speed of an object is computed as

Where x is the distance traveled and t the time taken for that. The time can be computed by

If
is the time for the upstream travel and
is the time for the downstream travel, then

Siince the same distance x= 10 miles is traveled in both cases:

Simplifying and rearrangling

Operating

Solving for 



If N=3

We can use the required value of N to compute the speed of the boat as explained
Answer:
0.0192A
Explanation:
Since, the reading of the galvanometer is 0 A, the voltage across the resistance R will be:
Step 1
VR = V2
VR = 3.00v
Step 2
Calculating the current through the resistance R as below,
IR = V1 - V2 /R1
IR = 12 - 3 /468
IR =0.0192A
If the separation distance is doubled, then the electric field decreases by a factor of 4.
<h3>What is the electric field strength?</h3>
We know that the electric field strength is known to depend on the magnitude of the charge and the distance of separation. We know that the electric field refers to the region in which the influence of a charge is felt. Recall that a charge is a specie that is positively or negatively charged. The charge on a specie must always be shown by its sign.
We know that the electric field is the region in space where the influence of a charge can be felt. If a charge is placed in the vicinity of another charge, the second charge would experience a force due to the presence of the first charge. This is because the second charge was brought into the electric field of the first charge.
Thus we know that;
E = Kq/r^2
Where;
E = electric field strength
q = magnitude of charge
r = distance of separation
Now;
E = 9.0* 10^9 * 3.052 * 10^-6/(8.22 * 10^-2)^2
E = 4 N/C
Given that the electric filed strength is inversely proportional to the distance of separation, when the distance between the charges is doubled, the electric field decreases by a factor of 4.
Learn more about electric field strength:brainly.com/question/15170044?
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Answer:
90 degrees
Explanation:
the answer is 90 because angle a has a square on the angle which means it is 90 degrees
Radiation is a type of heat transfer wherein there is no need for medium or media through which the heat will flow. Consequently, the radiation waves are able to travel through vacuum. The best observation as evidence to conclude that heat is indeed transferred by radiation is the increase of temperature of the receiving body.