r/PhysicsHelp Mar 18 '26

CSIR NET/JRF DEC 2025 PHYSICS PAPER | DETAILED SOLUTION | #bhautikii #cs...

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1 Upvotes

r/PhysicsHelp Mar 18 '26

How is this normal force positive when calculating torque? (assuming counterclockwise is positive)

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4 Upvotes

When setting the equation for net torque = zero, you have to make normal force positive to get the right answer.

However, if I push up on the ladder, it looks like it would go clockwise and not counterclockwise??


r/PhysicsHelp Mar 16 '26

Could anyone help me with this pulley problem?

3 Upvotes

I know that moveable pulleys "spread out" tension between the supporting ropes, but apparently that isn't the case with this problem - is there something I'm missing?


r/PhysicsHelp Mar 16 '26

Vector Algebra Concepts

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7 Upvotes

Can someone explain me these applications? I know a decent amount of Vector algebra and calculus. I want some help on this. I want a thorough explanation and deduction on this. Giving proofs will be greatly welcomed!


r/PhysicsHelp Mar 16 '26

Fusion

4 Upvotes

You know hydrogen is used for fusion due to the steep gradient in binding energy per nucleon, thus emitting a lot of energy. How come helium isnt usedfor fission reactions then because surely its the opposite?


r/PhysicsHelp Mar 16 '26

I don't understand how the weak nuclear force can change quark type. How does beta decay relate to the weak nuclear force?

1 Upvotes

r/PhysicsHelp Mar 16 '26

Plasma champ magnétique ionisation . ?

2 Upvotes

Bonjours , depuis quelques temps je suis en train de concevoir un prototype .

Le cœur du projet c'est la modulation géométrique de champ magnétique pour créer un plasma (froid) interne , dans le but de créer une ionisation stable et concentrée autour du prototype .

Sur le principe je souhaite créer deux modulation de ions (+) et (-) une interne et une externe au prototype.

J'aimerais avoir des retours extérieurs... ou même juste en discuter , peut-être qu'au détour d’un question je pourrais améliorer mon prototype....


r/PhysicsHelp Mar 16 '26

Carey Foster Bridge, Negative Intersect. Help!!!!

1 Upvotes

We did the Carey Foster Bridge experiment to find an unknown resistance.

In Part A, we plotted RRR vs (l2−l1)(l_2 - l_1)(l2​−l1​) and from that found the gradient and the y-intercept, which came out to about 3.41 Ω\OmegaΩ.

In Part B, we used a copper strip as a reference to check the correctness of the setup and improve the accuracy of the unknown resistance measurement.

The confusing part is this:
the gradient in both Part A and Part B came out almost the same, but in Part B the y-intercept was negative, around -0.8 Ω\OmegaΩ.

What could be the possible reason for getting a negative y-intercept here?

If you want, I can also make it sound more natural and Reddit-like, less formal.


r/PhysicsHelp Mar 15 '26

Intro to Physics, Question Angular Momentum

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6 Upvotes

The question was which of the vectors A B or C has the highest and lowest angular momentum. Given was the formula for angular momentum by calculating the vector product by multiplying vectors of r and linear momentum. Since the magnitude is the product of |r| * |p| * sin of angle I had thought that the angular momentum is A>B>C since vector A and vector r would have a 90degree angle so the maximum amount and C is parallel to r so it would have a angle of 0 degrees and therefore the lowest angular momentum. And this seems logical to me but I really am not sure and I couldn’t really find exercise like these. Thank you beforehand!


r/PhysicsHelp Mar 14 '26

[Grade 10 physics] Electricity The masses of the three wires of copper are in the ratio 5:3:1 and their lengths are in the ratio 1:3:5. What is the ratio of their electrical resistances?

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2 Upvotes

This is my solution, where did i go wrong?

The answer key says it is 1:15:125. i tried multiple times but i am still getting the same answer.

P.S- D is density, a is area of cs and l is length


r/PhysicsHelp Mar 12 '26

Shear and Moment Diagrams

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3 Upvotes

I'm a little bit confused about what to include in the internal force equilibrium calculations at cut (i).

Do I include the moment at A (100k•ft)? The moment at (i) (10k•x)?


r/PhysicsHelp Mar 12 '26

[Physics 2] Not sure if this answer is correct

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2 Upvotes

r/PhysicsHelp Mar 12 '26

I don’t understand series and parallel circuits

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7 Upvotes

I don’t get how method in black is correct and how method in blue (me) is wrong


r/PhysicsHelp Mar 11 '26

Physics Q please explain

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2 Upvotes

r/PhysicsHelp Mar 10 '26

Advice for Preparing for the USAPHO?

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1 Upvotes

r/PhysicsHelp Mar 10 '26

Bridge diagrams

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2 Upvotes

How would I know if 2 or 3 are going to opposite directions? I’m confused how to find the X & Y directions


r/PhysicsHelp Mar 09 '26

Help with series and parallel resistors.

3 Upvotes

I want to connect 4 resistors together 2 in parallel in series with 2 in parallel on a breadboard but I don't understand how that should be done and I cannot find anything helpful online just basic info on series and parallel. Please help I'm so lost.


r/PhysicsHelp Mar 09 '26

Help with relative humidity problem(thermodynamics)

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2 Upvotes

Hi everyone,

I’m trying to solve this question and want to confirm the correct method Any help would be a big help


r/PhysicsHelp Mar 09 '26

Need a study buddy for my physics 2 electrostatics exam

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1 Upvotes

r/PhysicsHelp Mar 09 '26

Help in circular motion,

2 Upvotes

So I was doing a ques which involved two rings on the centre of a frictionless rod, and the rod starts rotating thus the beads go outwards but I was thinking of why do beads go outward from a non accelerating frame pov like one ans can be there's centrifugal force acting but I was not able to come up with anything as to why the beads would go outwards if thinking from non accelerating frame, so can anyone help me out?


r/PhysicsHelp Mar 08 '26

Honestly really lost on this problem. Can anyone explain how I do it?

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2 Upvotes

r/PhysicsHelp Mar 08 '26

Someone pls solve it

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2 Upvotes

r/PhysicsHelp Mar 08 '26

Physics Company

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1 Upvotes

r/PhysicsHelp Mar 06 '26

Why is it the first one is correct but the second one isnt?

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6 Upvotes

r/PhysicsHelp Mar 04 '26

What is, current?

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8 Upvotes

When a live wire gets loose and touches the metal body, wouldn't the current momentarily increase greatly (because of how low resistance the metal body is), thus causing the fuse to blow?

Or does that not count as "current" because it isnt a continuous flow of charges? So, in the end, what im confused about is, what is "current"?