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
I think the correct answer would be the child quietly sits until the timer goes off. It is ineffective because the child would be used to this process and would come to a time where he will not get something from it.Also, it would make a child feel isolated and alone which would affect hi self-esteem in a long run.
Answer:
Explanation:
2 )
power of an electric device = V² / R where V is volts and R is resistance
putting given data
power = 9²/ 5
= 16.2 J/s
energy produced in 7 minutes
= 16.2 x 7 x 60
= 6804J .
3 ) Power of an electrical device
= V² / R
= V X I where I is current
= 4.5 x .5
= 2.25 W or J/s
4 )
energy used in 3 minutes with power of 2.25 W
= 2.25 x 3 x 60
= 405 J .
7 )
power of a electrical device
= V x I
IR x I where R is resistance .
= I²R
putting given data
power = .005² x 50
= 1.25 x 10⁻³ W .
8 )
Energy used up by a 60 W bulb in 2.5 hours
= 60 x 2.5 x 60 x 60
= 5.4 x 10⁵ J .
Answer:
D
Explanation:
induction is the transfer of charge without contact between materials
