A photoelectric cell is an electronic device which is used to convert light energy into electric energy.The operation of this device is based on photoelectric effect.
Light of suitable frequency i.e greater or equal to threshold frequency will fall on the cathode maintained at negative potential.The electron emission will take place and these electrons are drifted towards the anode which is at positive potential.
Here,only those radiations will be capable of emitting electrons irrespective of surface barrier of metals whose energy is greater than the work function.
We know that the radiation having long wavelength has least energy as energy and wavelength are inversely proportional to each other.

Here h is the Planck's constant,c is the velocity of light.
Here we have been given red light and blue light.
In the visible spectrum of radiation, the red light has longer wavelength than all other colors of light.Hence blue light has more energy as it's wavelength is less as compared to red light.
Hence, the blue light will activate the most and red the least.
The second world war, and its war weapons, such as the v-2 rockets, had a great impact on the world until today, to answer this question we need that...
<h3>
V-2 factory </h3>
On April 11, 1945, US troops took the town of Bleicherode, in the Kohnstein region, where the V-2 factory was located. From there about 100 complete V-2s and thousands of parts and equipment were "captured" as war loot and transferred to the United States, where they formed the basis for practical studies of the missile defense program.
With this information, we can say that because it was a base discovered by US troops, none of the alternatives is correct, as it was not the Soviets who discovered it, and that the base was also located in the central part of Germany.
<u>The </u><u>v-2 factory</u><u> was located in </u><u>Kohnstein, central germany,</u><u> by this claim, </u><u>none of the alternatives is correct.</u>
Learn more about second world war brainly.com/question/7013432
Answer:
3.90 degrees
Explanation:
Let g= 9.81 m/s2. The gravity of the 30kg grocery cart is
W = mg = 30*9.81 = 294.3 N
This gravity is split into 2 components on the ramp, 1 parallel and the other perpendicular to the ramp.
We can calculate the parallel one since it's the one that affects the force required to push up
F = WsinΘ
Since customer would not complain if the force is no more than 20N
F = 20



So the ramp cannot be larger than 3.9 degrees
The answer is c
Explanation: