Answer:
Current in outer circle will be 15.826 A
Explanation:
We have given number of turns in inner coil 
Radius of inner circle 
Current in the inner circle 
Number of turns in outer circle 
Radius of outer circle 
We have to find the current in outer circle so that net magnetic field will zero
For net magnetic field current must be in opposite direction as in inner circle
We know that magnetic field is given due to circular coil is given by

For net magnetic field zero

So 

The relationship between the number of visible spectral lines are identical for atoms .However they have unique wavelengths.
Option B
<u>
Explanation:</u>
A spectrum is a range of frequencies or a range of wavelengths. The photon energy of the emitted photon is equal to the difference between two states. For every atom there are quite many electron transitions and each has a energy difference.
This difference in wavelength causes spectrum .As each element emission spectrum is unique because each atom has different energy and causes uniqueness in the emission spectrum . Hence, due to the difference in energy it emits different wavelengths.
Answer:
t = 2.5 hours
Explanation:
given,
speed of the bike for t time= 18 mi/h
final speed of the bike after t time = 12 mi/h
total distance, D = 69 miles
total time, T= 4.5 hour
time for which speed of the bike is 18 mi/h = ?
we know distance = speed x time
now,
18 x t + 12 (4.5 - t) = 69
6 t + 54 = 69
6 t = 15
t = 2.5 hours
The bike was at the speed of 18 mi/h for 2.5 hours.
We have that The Density and Volume is given as

The factors that affect Density are Mass and Volume
From the question we are told that
The piece of wood shown above has a mass of 20 grams.
Wood parameters
2cm
5cm
3cm
Generally the equation for the Volume is mathematically given as

Generally the equation for the Density is mathematically given as

Therefore the factors that affect Density are Mass and Volume
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<h3><u>Answer;</u></h3>
<em>Electric motor</em>
<h3><u>Explanation;</u></h3>
- <em><u>Energy</u></em> is the ability to do work. According to the law of conservation of energy,<em><u> energy can not be created nor destroyed but can be changed from one form to another</u></em>.
- Changing energy from one form to another is done by devices we call <em><u>transducers. These are elements that convert energy from one form to another.</u></em>
- In this case, electrical motor is an example of a transducer that converts electrical energy to kinetic energy. <em><u>Electrical energy is supplied to a the motor which converts it to rotational energy or mechanical energy then to kinetic energy.</u></em>