# Physics

posted by
**Ramin**
.

Please Help me on these:

3. What mathematical expression tells you to what percentage the charge is after n t1/2's?

(All these should be multiplied by 100% to obtain the percentage.)

2- n

V*C

e-t/τ

R*C

1 - 2^- n ((((((((((( I think this is right what do you think)))))))))))

R*C*ln2

4. What expression tells you what percentage is left to be charged at the same n t1/2's?

(All these should be multiplied by 100% to obtain the percentage.)

R*C

R*C*ln2

( 2n - 1 ) 2^- n ((((((((((( I think this is right what do you think)))))))))))

1 - 2- n

V*C

1-e-t/τ

2- n

5. Given a resistance of 165 Ω and a capacitance of 335 μF,

what is t1/2?

t1/2 = [milliseconds]

(Answer to one tenth of a millisecond or N/A if there is no answer.)

t1/2 = 38.3 Now I found this by doing this: 165*335 =55275 then 55275*Ln(2)=38313.71[milliseconds]

I don't know if this is right or not?

6. Given a resistance of 165 Ω and a capacitance of 335 μF,

what is the time constant τ (tau)?

τ (tau) = [units reserved for next question.]

Use normal unit for this answer not milli nor micro units.

τ (tau) = 55.3 I found this by simply multiplying 165*335 =55275

Use normal unit for this answer not milli nor micro units.

Again I am not sure if this is right or not please help.

7. What are the units of τ?

F

μF

second ((((((I think this is the answer what do you think))))))))

Volt

Amp

Coulomb

Volt/Amp

Coulomb Volt

Ω

8. You have an RC circuit and you measure the "zero" voltage to actually be -2.595 [Volts].

The peak voltage is measured to be 8.502 [Volts].

At what voltage value will you look for t5 = time stamp for 31/32 total charge?

[Volts] (((((((Please show me some steps on this i am extremely confused on this one.))))))))))))))))))))))))))))))))

(Use three significant figures or N/A if there is no answer.)