CRACKNEETPhysics

Most schools and Coaching Institutes would not teach you like this. Watch this Video if you think you have Doubts on Newtons second law o f Motion. Very Good Theory, Concept practise and MCQs. Step by Step .

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You stand on a spring scale in a lift. The scale reading becomes more than your weight for a short time and then returns to normal while the lift keeps moving upward. Which situation fits this record?


A. Lift starts upward and keeps speeding up
B. Lift moves upward at constant speed
C. Lift moving upward comes to a stop at an upper floor
D. Lift is moving downward and speeds up

19 hours ago | [YT] | 2

CRACKNEETPhysics

Two teams play tug-of-war on dry level ground. The rope is light and taut. At some instant the right team begins to slide left while the left team’s feet do not slip.

Which statement is correct?

A) The left team pulls the rope more than the rope pulls the left team.
B) The rope pulls both teams with equal magnitude, but the right team loses because the friction from the ground on the right team is smaller than that on the left team.
C) Since the right team accelerates left, the rope’s pull on the right team must be greater than the rope’s pull on the left team.
D) The net external horizontal force on the “two teams + rope” system is zero, so that system cannot accelerate

1 day ago | [YT] | 4

CRACKNEETPhysics

A straight conducting bar is made by joining two long segments in series, X and Y, each of the same length and the same cross-sectional area. A steady current flows from left to right when an ideal battery is connected. The free-electron density is the same in X and Y, but their resistivities are different (Y is the more resistive material). Temperature is constant.

Which one of the following statements is incorrect?

A) The current is the same through X and Y in steady state.

B) The electric field inside Y is stronger than inside X (since Y is more resistive) even though their cross-sections are the same.


C) The drift speed of electrons is larger in Y than in X because Y is more resistive, even when the cross-sections are equal.


D) A non-uniform surface charge distribution appears along the bar and at the X–Y junction to steer the field; reversing battery polarity flips the sign of these surface charges.

Did school/coaching leave your NEET Physics doubts unresolved? Subscribe here for crystal-clear concepts and exam-level practice questions—no formula cramming, just understanding.

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1 day ago | [YT] | 6

CRACKNEETPhysics

A solid metal bar AB is made of a single material with uniform resistivity. Its cross-section decreases smoothly from end A (thick) to end B (thin). The ends are connected to an ideal battery so that a steady current flows. Temperature remains constant.

Consider these statements about the steady state inside the bar:

A. The current is the same through every cross-section; the drift speed of electrons is larger near B than near A.

B.The electric field inside the bar has the same magnitude everywhere; only drift speed changes.

C.The potential falls uniformly from A to B (equal drop per unit length).

D. The surface charge along the bar is uniform, because the material is uniform

Did school/coaching leave your NEET Physics doubts unresolved? Subscribe here for crystal-clear concepts and exam-level practice questions—no formula cramming, just understanding. Watch this Video if your school/Coaching did not help you understand the concepts :- youtube.com/live/BnPaG87ku1c

2 days ago | [YT] | 4

CRACKNEETPhysics

A long straight conductor of radius a initially carries a steady current uniformly across its cross-section. A coaxial cylindrical hole of radius a/2 is drilled out (no current in the hole). The total current is kept the same by redistributing it uniformly in the remaining metal (the annular region). Let B(r) be the magnitude of the magnetic field at distance r from the axis.

Which statement about the shape of B(r) is correct?

A) B=0 for r<a/2 it then jumps to a finite value at r=a/2 , rises up to the surface, and falls outside.

B) B=0 for r<a/2 and also remains 0 just outside r=a/2 ; it becomes non-zero only near r=a .

C) B≠0 inside the hole because the surrounding current shell acts like an external wire.

D) B=0 for r<a/2 ; at r=a/2 the value of B is the same from inside and just outside (no jump), but the slope changes: for a/2<r<a it increases with r, then beyond r=a it decreases with distance.

Solution https://www.youtube.com/watch?v=oWMix...

3 days ago | [YT] | 5

CRACKNEETPhysics

Two identical long solenoids share the same axis; one is slid inside the other so their bores coincide. Both carry the same current magnitude.

Case I: Currents in the same direction.

Case II: Currents in opposite directions.

Which statement best describes the resultant field far from the ends?

A) Case I: nearly double inside, almost zero outside; Case II: almost zero everywhere except small end regions.
B) Case I: zero inside; Case II: doubled inside.
C) Both cases: zero inside due to cancellation.
D) Both cases: strong outside, weak inside.

Solution :- https://youtu.be/3V_oric5g_k?si=xmaNP...

https://youtu.be/VnoFW1uu6_c

https://youtu.be/M8v9y7rzn20

youtube.com/live/YEJZIk1MauU?feature=share

3 days ago | [YT] | 3

CRACKNEETPhysics

Gauss’s Law in Magnetism — quick, friendly reminder

What it says (one line):
No magnetic monopoles ⇒ total magnetic flux through any closed surface is zero.
(Magnetic field lines never start or end; they always form closed loops.)

Picture to keep in mind:
Imagine rubber-band loops (field lines) threading space. Draw any closed bubble (sphere, cube, weird potato). For every line that enters the bubble, it must leave somewhere else. Enters = leaves ⇒ net flux = 0.

Bar magnet trap:
Even if your bubble surrounds the “north” end of a bar magnet, lines that enter from the sides/inside also leave—you can’t trap an isolated pole with a closed surface.

Solenoid reminder:
A surface capping the bore has strong inward/outward flux, but the small, spread-out outside flux + edge effects exactly cancel it → net zero.

Time-varying fields:
Current changing, fields changing… still no magnetic charge. Net flux through a closed surface remains zero.


5-second checklist

Closed surface? → 0 net flux

Open surface? → use dot with the area direction and symmetry

Watch end effects and sign conventions

Beware “isolated pole” language

Revisit the theory short notes: field lines = closed loops, no monopoles, net flux through any closed surface = 0. Once this is burned in, most Gauss-law-in-magnetism MCQs collapse to one-step answers.


QUESTION

A closed surface S is drawn in each situation below. Decide which single claim about the net magnetic flux through

S is correct.

A) S cuts a bar magnet so that only the “north” face lies inside while the “south” face is outside. Therefore the net flux through S is positive.

B) S is threaded by a long straight wire carrying steady current. Since field lines circle the wire and pierce
S , the net flux through S is non-zero.

C) S encloses one circular end-cap inside the bore of a very long solenoid, while the rest of S lies outside where the field is tiny. The net flux is zero.

D) In case (B), if the current is ramped with time, “displacement current” acts like magnetic charge, so the net flux through S becomes non-zero.


Watch This Video Fully :- youtube.com/live/lxUiFbAxDuE?si=uaSVq2UZadJY9e9N

3 days ago | [YT] | 4

CRACKNEETPhysics

A solid sphere is given a backward spin (opposite to rolling direction) and gently released on a rough incline. Initially, static friction acts:


A. Up the plane 
B. Down the plane 
C. Zero 
D. Random—depends on μs only

Solution :- https://youtu.be/BEi53meUGh4

Hint ;- Think of a basketball on a sloped driveway. Give it a backward spin and gently place it on the slope. The rubber at the bottom would try to skid downhill. Now ask: Which way must the ground’s grip pull to stop that skid?
If you can name that direction, you’ve got the friction direction.

4 days ago | [YT] | 7

CRACKNEETPhysics

A long, tightly-wound solenoid produces a nearly uniform field inside its bore. Keeping the current the same, the following changes are made one at a time:

P. The coil is stretched to twice the length (total turns fixed).
Q. A soft-iron core is inserted.
R. The current is reversed.
S. The winding is made non-uniform: first half tightly packed, second half loosely spaced.

Which change(s) reduce the uniformity of the field inside (not just its strength/direction)?

A) S only
B) P only
C) P and S
D) P, Q, R and S

Solution :- https://youtu.be/VnoFW1uu6_c

5 days ago | [YT] | 4

CRACKNEETPhysics

A balloon carries two climbers of masses 60 kg and 80 kg; the rest of the system is 280 kg. From rest, they climb up the ladder at constant speeds 1.2 m/s and 1.5 m/s, respectively. Neglect drag and buoyancy change. The balloon’s speed is closest to

Solution :- https://youtu.be/HMuOM-6LzlU?si=sEMGk...

5 days ago | [YT] | 7