# [J2] Term 1 Week 3 (20-22 Jan & 30 Jan-2 Feb) Updates/ Debrief

[J2 Physics PMCians] Rayleigh’s criterion and all about Stationary Waves

What we did in 2 hours:

We extended the importance of single slit diffraction to why there is a limit in our eye’s ability to resolve 2 objects at a distance. That’s where Rayleigh’s criterion helps us to find the limit of our ability.

We ended the lesson by asking, what happens when 2 waves move in opposite direction to each other? You get a Stationary Wave!! And we summarised the 2 types of equations needed to analyse any stationary wave.

What you take home:

Please try the remaining questions as homework. You can find the link to the solutions here:

1) Stationary waves:

https://tinyurl.com/wqrq5fb

2) Single Slit:

https://tinyurl.com/w9jcdur

In the next lesson, we will revise all you need to know for Electric Field.

[J2 Maths PMCians] Applications of Integration

What we did in 2 hours:

Having moved on to Applications of Integration, we revised the various methods of obtaining Area Under a Curve & Volume of Revolution. Do note the new style of Enclosed Areas (Parametric) which schools will be setting this year, in response to last year’s A levels question.

*RI Class* have finished our Integration Techniques, we moved on to some introduction to Applications of Integration. This week we will follow-up on that and pick up all the remaining Applications of Integration.

What you take home:

Other than a newfound love for obtaining volumes, you also have some extra practice questions for Applications of Integration. The worked solutions are linked here:

https://tinyurl.com/shgnaxg

Special Mention:

This week we will attempt the remaining Apps of Integration questions, which can be challenging. Come prepared! We will also be starting on Differential Equations Revision.

[J2 Chemistry PMCians]

What we did in 2 hours:

This week, we completed our revision on Arenes, and have moved on to our lesson on Halogen Derivatives. More specifically, these concepts were covered:

• Electrophilic Substitution of Arenes
• Directing Effect of Substituents in Benzene
• 4 Reactions of Halogenoalkanes

In the next lesson, we shall look at the nucleophilic substitution mechanism (SN1 and SN2) and end of the lesson with aryl halides and ease of hydrolysis.

For the RI class, we have covered Acid-Base Equilibrium in the previous lesson. The concepts covered are:

• Definitions of Acids & Bases
• Strength of Acids & Bases
• Self-Ionisation of Water

Next lesson, we shall learn how to calculate pH of various solutions and investigate salt and buffer solutions.

Many of you have asked what refluxing a reaction mixture means. This is a quick video to explain the rational and methods of reflux:

What you take home:

The solutions to the Structured Questions inside your Hydrocarbons booklet is also found here:

https://tinyurl.com/wqux3lu

Special Mention:

For the RI/EJC (Wed) class, lessons will resume this coming Wednesday (05/02).

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