For a constant resistance, how is the voltage related to the current? a) voltage is inversely proportional to current, so when the voltage doubles, the current is cut in half. b) voltage is directly proportional to current, so when the voltage doubles, the current is cut in half. c) voltage is inversely proportional to current, so when the voltage doubles, the current doubles. d) voltage is directly proportional to current, so when the voltage doubles, the current doubles.

Option (D) is the correct answer.

Explanation:

According to the ohm's law, the voltage across a resistor is directly proportional to the product of current and resistance.

Mathematically,     V = I × R

where,      V = voltage

                 I = current

                 R = resistance

Therefore, it means voltage is directly proportional to the current. So, if resistance is constant then with increase in voltage there will also occur increase in the current.

Thus, we can conclude that for a constant resistance, voltage is directly proportional to current, so when the voltage doubles, the current doubles.

.) the observation by semmelweis that more mothers died of childbed fever when their doctors also worked in the morgue

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.