Capacitance is a measure of charge stored per volt.
Answer:
The question is not complete. see the complete question in the explanation section. The correct option is highlighted in bold
Explanation:
(a)A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. At the moment contact is made with the battery, the voltage across the resistor is
I. greater than the battery's terminal voltage.
II. equal to the battery's terminal voltage.
III. less than the battery's terminal voltage, but greater than zero.
IV. zero.
<em>Option (i) is not correct as the voltage across the resistor cannot be greater than the terminal voltage since the current is yet to flow through the resistor. Option (ii) is correct as both the resistor voltage and the terminal voltage will just equal at the instance of connection. Option (ii) can only be possible after the current must have passed through the resistor for a while not immediately after contact. Option (iv) is not correct, as this can only be possible is the contact is open.
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(b)A resistor and a capacitor are connected in series across an ideal battery having a constant voltage across its terminals. At the moment contact is made with the battery the voltage across the capacitor is
I. greater than the battery's terminal voltage.
II. equal to the battery's terminal voltage.
III. less than the battery's terminal voltage, but greater than zero.
IV. zero.
<em>Option (i) is not correct as the capacitor is yet to charge talk less of the its voltage exceeding that of the battery. Option (ii) can only be correct if the capacitor is fully charged not when it has just been connected. Option (iii) can only occur if the capacitor is discharging. Option (iv) is the correct answer as the capacitor is about to start charging
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Speed decreases more the denser the medium.
Since density of a material normally decreases with temperature, it is not surprising that the speed of light in a liquid will normally increase as the temperature increases. (Thus, the index of refraction normally decreases)
Amount of charge on the capacitor=q=10⁻³C
Energy stored=4.5x10⁻³ J
potential difference= 9 V
Energy stored= E= 1/2 q V
4.5x10⁻³ =1/2 q (9)
q=10⁻³C
Thus the amount of charge on the capacitor=q=10⁻³C
Answer:
k = 1755 N/m
Explanation:
Given:
- The length of the cord L = 23.4 m
- Weight of the student W = 818 N
- The elevation of balloon H = 31.3 m
Find:
Calculate the required force constant of the cord if the student is to stop safely 2.74 m above the river.
Solution:
- We know the potential energy of the student changes by
ΔP.E = m*g*( H - 2.74 )
mg*(31.3 - 2.74) = 818*28.56 = 23362.08 J
- When he stops at 2.74 m above ground his KE = 0 so ALL his lost potential energy must be stored in the extended or stretched bungee cord.
- He falls 23.4 m before the bungee cord starts to stretch. That means it doesn't start stretching until he is 31.3 - 23.4 = 7.9 m above the ground.
- It has to stop stretching at 2.74 m above the ground so the
total stretch = 7.9 - 2.74 = 5.16 m
- Therefore his PE from 31.3 m to 2.74 m is stored in a 5.16 m stretch of the bungee cord.
½kx² = ΔP.E
k = 2*ΔP.E / x^2
k = 2*23362.08 / 5.16^2
k = 1755 N/m
