In a circuit, a variable resistor is to be connected across a potential difference of 60 volts to allow the current to be adjusted in the range from 40 milliamperes to 100 milliamperes. A variable resistor is a device in which the resistance can be varied.
mA = milliamperes, or 10-3 amperes
Over what range must the resistance vary?

plz help :')

600 and 1500 [ohm

Explanation:

To solve this problem we must use ohm's law, which tells us that the voltage is the product of the current by the resistance, so we have:

V = I*R

where:

V = voltage [V]

I = current [amp]

R = resistance [ohm]

Therefore:

R = V/I

R1 = 60/(40*10^-3) = 1500 [ohm]

R2 = 60/(100*10^-3) = 600 [ohm]

So the resistance should be among 600 and 1500 [ohm]

the arctic is a region of the planet, north of the arctic circle, and includes the arctic ocean, greenland, baffin island, other smaller northern islands, and the far northern parts of europe, russia (siberia), alaska and canada.

answer: the exterior temperature of commercial jet planes as they leave the stratosphere and return to the ground increases steadily.

explanation:

the lower most layer of atmosphere is troposphere which extends from 0 to 12 km above the surface of the earth. the temperature initially decreases as distance is increased from the earth's surface. commercial jets fly in lower part of the stratosphere. the stratosphere extends upto 50 km. the temperature in stratosphere starts rising again due to presence of ozone which traps the uv rays.

thus, when the planes leave the stratosphere and return to the ground, the exterior temperature increases steadily.