The focal length of the lens is 25cm
given:
power,p=4 diopters
what is focal length?
Focal length is the distance between the point of convergence of your lens and the sensor or film recording the image.
what is diopter?
The unit of optical power of lens is called diopter.It is the optical power of the lens.
we know,
p=1/f
where,
p= power
f= focal length
f=1/p
f=1/4
=0.25m
=25cm
Thus,the focal length of the lens is 25cm
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Answer:
579600J
Explanation:
Given parameters:
Height of the building = 828m
Weight of the man = 700N
Unknown:
Work done by the man = ?
Solution:
The work done by the man is the same as the potential energy expended.
Work done:
Work done = Weight x height = 700 x 828
Work done = 579600J
Angular frequency in radian per second for 20 vibrations in 10 seconds is 12.6 rad/s
<h3>What is Angular frequency?</h3>
Angular frequency is the number of vibrations in radian per second.
The total number of vibrations n is 20 and the time taken for these vibrations is 10 s
The frequency of the vibrations will be
f = 20 / 10 = 2 Hz
Angular frequency is related to the frequency as
ω = 2πf
ω=2π × 2
ω = 12.6 rad/s
Thus, the angular frequency is 12.6 rad/s.
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Answer:
The average induced emf in the coil is 0.0286 V
Explanation:
Given;
diameter of the wire, d = 11.2 cm = 0.112 m
initial magnetic field, B₁ = 0.53 T
final magnetic field, B₂ = 0.24 T
time of change in magnetic field, t = 0.1 s
The induced emf in the coil is calculated as;
E = A(dB)/dt
where;
A is area of the coil = πr²
r is the radius of the wire coil = 0.112m / 2 = 0.056 m
A = π(0.056)²
A = 0.00985 m²
E = -0.00985(B₂-B₁)/t
E = 0.00985(B₁-B₂)/t
E = 0.00985(0.53 - 0.24)/0.1
E = 0.00985 (0.29)/ 0.1
E = 0.0286 V
Therefore, the average induced emf in the coil is 0.0286 V
Answer:
Q stay the same
Explanation:
Charging of capacitor is done by battery . If battery is disconnected , charging will stop . There will not be any discharging as plates are separate . So pulling the plates apart will not affect the charge lying on the capacitor . It will decrease its capacity and increase its potential , keeping its charge constant.