The second question has the answer of A
the fact or phenomenon of light, radio waves, etc. being deflected in passing obliquely through the interface between one medium and another or through a medium of varying density.
Answer:
Spirometry is a type of pulmonary function test (PFT), a noninvasive procedure that provides important information about how well the lungs are working. More specifically, it reveals how much air is moving through the lungs and how quickly as you breathe through a tube.
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I think it's electric force. Not 100% sure but I hope it's right.
A force of 8 N will be required.
<h3><u>Explanation:</u></h3>
Mechanical advantage is defined as the ratio of output force from a system to the input force into the system. A machine which has the mechanical advantage more than 1 means it requires less force to give more force as output. Similarly, when the mechanical advantage for the machine is less than 1,it means more force is required to give to achieve a less one.
Here in the question, the mechanical advantage of the pulley is 2.
Output force required to pull the sack of potatoes upto kitchen is 16N.
Mechanical advantage = Output force / input force.
Or, 2= 16 / input force.
So input force = 
So a force of 8 N will be required to pull the pulley.