Given :
The focal length of a concave mirror is 18 cm.
To Find :
The radius of curvature of the concave mirror.
Solution :
We know,

Therefore, the radius of curvature of concave mirror is 36 cm.
Hence, this is the required solution.
Well, electrons can be converted into a atomic number so if SE atomic number is 34 that means it has 34 electrons. AI has a atomic number of 13 meaning it has 13 electrons.
So the difference is that SE has more electrons then AI.
Hope this helped. :D
Answer:
The solar cells transfer light energy to thermal energy.
When the battery is being charged up, chemical energy is transferred to electrical energy.
The motor is designed to transfer potential energy to kinetic energy.
Complete question:
Two 10-cm-diameter charged rings face each other, 21.0 cm apart. Both rings are charged to +40.0 nC. What is the electric field strength at the midpoint between the two rings ?
Answer:
The electric field strength at the mid-point between the two rings is zero.
Explanation:
Given;
diameter of each ring, d = 10 cm = 0.1 m
distance between the rings, r = 21.0 cm = 0.21 m
charge of each ring, q = 40 nC = 40 x 10⁻⁹ C
let the midpoint between the two rings = x
The electric field strength at the midpoint between the two rings is given as;

Therefore, the electric field strength at the mid-point between the two rings is zero.
<span>Power is measured in watts. A watt is the power that it takes to do one joule ofwork in one second. It can be found using the formula <span>P=<span>Wt</span></span>. (In this formula, W stands for "work.")</span><span><span>Large amounts of energy can be measured in kilowatts (<span>1kW=1×<span>103</span>W</span>), megawatts (<span>1MW=1×<span>106</span>W</span>), or gigawatts (<span>1GW=1×<span>109</span>W</span>).</span><span><span> This is helpful</span><span> This is confusing</span></span></span><span>The watt is named James Watt, who invented an older unit of power: the horsepower.</span>