Answer:
<em>Pure water </em><em>won’t conduct electricity</em>
<em>Option A</em>
Explanation:
Pure water doesn’t contain salts or impurities. It is the salts that dissociate to form ions that act as charge carriers in conducting solutions. For a medium to conduct electricity it should have carriers to carry the electrical charge.
Thus absence of charge carriers make pure water non conducting. Charge carriers in metals are electrons and in ionic solutions they are positive and negative ions.
Tap water, aquarium water and ocean water contains dissolved electrolytes. When electricity is passed through them the electrolytes dissociates into ions and these ions conduct electricity.
Answer: barometer
Explanation: An instrument that measures air pressure is called a barometer. One of the first barometers was developed in the 1600s. The original instrument had mercury in the small basin, with an upside down glass tube placed in the mercury.
Given that,
Angle = 30°
Initial velocity = 15 m/s
We need to calculate the time of flight
Using formula of time of flight
Where, u = initial velocity
g = acceleration due to gravity
Put the value into the formula
We need to calculate the final velocity of the ball
Using equation of motion
Hence, The final velocity of the ball is 29.7 m/s.
t = total time taken by sound to go down the well and then come back = 2 sec
d = depth of the well
D = total distance traveled by the sound
total distance traveled by sound is given as
total distance traveled = distance traveled going down + distance traveled going up
D = d + d
D = 2 d eq-1
v = speed of sound = 343 m/s
we know that distance traveled is given as
total distance traveled = speed of sound x total time
D = v t
using eq-1
2 d = v t
2 d = (343) (2)
dividing both side by 2
d = 343 x 2/2
d = 343 m
hence surface of water is 343 m deep