## FANDOM

3 Pages

Andrew, please read EVERY SINGLE WORD on this page carefully before downloading new questions.

## 4 February 2018 NEW!

• Question 8: Let $V$ be the EMF. When the ammeter has a resistance $r$, the current $I$ passing through the circuit will be given by $I = \frac{V}{300}(1 - 3%)$. Next, can you set up an equation linking $V$, $I$, and $r$? Finally, solve for $r$.
• Question 9: I repeat, please note that $\frac{a}{b + c} \neq \frac{a}{b} + \frac{a}{c}$. For example, $\frac{1}{2 + 3} \neq \frac{1}{2} + \frac{1}{3}$. Also, I repeat, there is NO REASON to believe that the current flowing through the two circuits will be the same. Only the EMF will be the same. What is the EMF? In the second circuit, what is the current flowing through the resistor NOT connected to the voltmeter? What is the current flowing through the resistor connected to the voltmeter? What is the current flowing through the voltmeter?
• Question 10(a): As mentioned below, 3 V is the potential difference across the whole circuit. It cannot be used in this part of the question.
• Question 10(b): Since your answers in part (a) is incorrect, your answers here are incorrect too.
• Question 10(c): Find out the correct potential difference across resistor X first.
• Question 10(d): Your answer is obviously incorrect.
• Work out Question 11 on your own.

## 2 February 2018

Do corrections and think about the following points:

• Question 7: Let $\varepsilon$ be the EMF, $r$ be the internal resistance of the battery. Since there are two unknowns, you have to set up two equations. What is the current flowing through the circuit when S1 is closed? What is the current flowing through the circuit when S2 is closed?
• Question 8: Your equation is wrong. Why would $V = \frac{I}{R}$? Let $V$ be the EMF and $r$ be the resistance of the ammeter. What would be the reading of the ammeter (in terms of $V$) when the ammeter has no resistance? What would be the reading of the ammeter when it has an error of 3%?
• Question 9: Your answers are completely wrong. Why did you assume that the current would be the same? Only the EMF would be the same. Please also note that $a(\frac{1}{b} + \frac{1}{c}) \neq \frac{a}{b + c}$.
• Question 10: If you want to use 3 V in your calculation, then the $R$ has to stand for the resistance of the WHOLE circuit. Please re-do this question. You should be able to complete it without any hint.
• Question 11: Think about this question by yourself.

## 28 January 2018

Homework:

• Explain why an ideal voltmeter has an infinitely high resistance.
• Do corrections for the questions on p.178 and p.179. Think about the following points.
• Question 2: What is the potential drop across the resistor? What is the potential drop across the internal resistance of the cell? What is the internal resistance of the cell?
• Question 3: Your answer is wrong. What is the equivalent resistance of the whole circuit? What is the current flowing through the circuit? What is the potential drop across the resistor on the right? What is the potential drop across the resistor on the left?
• Question 4: You are almost there. What is the potential drop across X? What is the current flowing through X?
• Complete questions on p.180.

## 26 January 2018

Homework: Complete questions on p.178 and p.179.

Homework:

No homework!

## 9 January 2018

Homework:

• Read your physics textbook.
• Complete your physics past paper.

Homework:

## 5 January 2018

Homework:

• Complete your mathematics past paper.
• Check your answers and do corrections using another pen.

## 2 January 2018

Homework:

• Please send me your past papers (including answers).
• Complete Questions 4 and 5 about voltage.
• Read p.94 to p.107 of your physics textbook and complete these questions.

## 31 December 2017

Please take note of the following points when you do corrections for Question 24:

• Draw a free-body diagram.
• What is the direction of the electric field strength?
• What is the direction of the net force?
• Is there any acceleration in the horizontal direction?
• Is there any acceleration in the vertical direction?
• What is the vertical distance travelled?
• What is the time taken?
• What is the horizontal distance travelled?

Recall the four equations of motion:

• $s = \frac{1}{2}(u + v)t$
• $s = ut + \frac{1}{2}at^2$
• $v = u + at$
• $v^2 = u^2 + 2as$

Homework:

• Do corrections for Question 24.
• Do corrections for the questions on electric circuits.
• Read p.84 to p.91 of your physics textbook and complete Questions 1 to 5.

## 28 December 2017

Please take note of the following points when you do corrections:

• Draw free-body diagrams for all questions.
• Question 17: Note that electric field strength is a vector quantity. Recall the addition of forces. How did you do that? The addition of electric field strengths is similar.
• Question 18: Note that the metal ball is a conductor. In other words, there will be induced charges. What would be the charge distribution on the ball? Note that electric field lines originate from positive charges and end in negative charges.
• Question 19: Is there any net force acting on the proton? Is there any acceleration? How do you calculate work done (learnt in Form 4)? Note that energy is conserved. In other words, the work done will be transformed into another form of energy.
• Question 23: Is there any net force acting on the electron? Is there any acceleration? What is their direction? What would happen after passing through B?
• Question 24: Is there any net force acting on the electron? What is its direction? Is there any acceleration in the horizontal direction? In the vertical direction? What kind of motion is this? Recall what you learnt in Form 4!

Recall the four equations of motion:

• $s = \frac{1}{2}(u + v)t$
• $s = ut + \frac{1}{2}at^2$
• $v = u + at$
• $v^2 = u^2 + 2as$

Homework:

• DO CORRECTIONS.
• Read p.74 to p.81 of your physics textbook and complete these questions.

## 26 December 2017

Notes:

• Always draw free-body diagrams.
• The equation $E=\frac{1}{4\pi\varepsilon_0}\frac{Q}{r^2}$ is only applicable to electric fields around point charges. It is NOT applicable to electric fields generated by two parallel plates.

Homework:

## 24 December 2017

Homework:

Next Tutorials:

• 26 December 11:00
• 28 December 11:00

## 22 December 2017

Homework:

• Read p.4 to p.64 of your physics textbook.
• DO CORRECTIONS AND COMPLETE ALL UNFINISHED QUESTIONS.
• Complete Questions 16 to 19.

Homework:

## 17 December 2017

Homework: After reading p.4 to p.64 of your physics textbook, complete Questions 11 to 15.

Next Tutorials:

• 19 December 17:30
• 22 December 17:30
• 24 December 14:00

## 15 December 2017

Homework: After reading p.4 to p.64 of your physics textbook, complete these MC questions. Please show ALL steps.

## 12 December 2017

Homework: Complete Questions 11 to 18.

## 8 December 2017

Homework: After reading p.4 to p.64 of your physics textbook, complete these questions.

Next Tutorials:

• 12 December 17:30
• 15 December 17:30
• 17 December 14:00