Answer:
B ) Ascend using my buddy alternative air source / make an emergency Ascent
Explanation:
From the description it can be seen his buddy is close by of which he can easily use the alternative air source. Also we can see that he is closer to the water surface than his buddy, of which controlled emergency swimming ascent is highly favourable in this condition.
1.96s and 1.86s. The time it takes to a spaceship hovering the surface of Venus to drop an object from a height of 17m is 1.96s, and the time it takes to the same spaceship hovering the surface of the Earth to drop and object from the same height is 1.86s.
In order to solve this problem, we are going to use the motion equation to calculate the time of flight of an object on Venus surface and the Earth. There is an equation of motion that relates the height as follow:

The initial velocity of the object before the dropping is 0, so we can reduce the equation to:

We know the height h of the spaceship hovering, and the gravity of Venus is
. Substituting this values in the equation
:

To calculate the time it takes to an object to reach the surface of Venus dropped by a spaceship hovering from a height of 17m, we have to clear t from the equation above, resulting:
Similarly, to calculate the time it takes to an object to reach the surface of the Earth dropped by a spaceship hovering from a height of 17m, and the gravity of the Earth
.

Answer: a. forms where light rays coming from the dog converge.
Explanation:
While photographing through digital camera, the light from the object through the lens converges and falls on image sensor.
The image breaks into many pixels and color and brightness of each pixel is measured and stored in form of number. This forms a digital image.
Thus, the correct option is a because the lens converges the light coming from the object onto the sensor.