CRACKNEETPhysics

Assertion (A): If the intensity of incident light on a metal surface is doubled while keeping the frequency constant, the maximum kinetic energy of the emitted photoelectrons will also double.

Reason (R): According to the photoelectric equation hν = hν₀ + K.E., the threshold frequency (ν₀) is an intrinsic property of the metal and remains constant regardless of the intensity of the incident light.

Choose the Correct Option:
A) Both (A) and (R) are true, and (R) is the correct explanation of (A).
B) Both (A) and (R) are true, but (R) is NOT the correct explanation of (A).
C) (A) is true, but (R) is false.
D) (A) is false, but (R) is true.

Answer open.substack.com/pub/crackneetphysics/p/understan…

25 minutes ago | [YT] | 0

CRACKNEETPhysics

An aqueous solution of sodium hydroxide (NaOH) is labeled as 10% (w/w). The density of this solution is recorded as 1.070 g cm⁻³. Based on the atomic masses provided (Na = 23, H = 1, O = 16), which of the following represents the correct molarity, molality, and mole fraction of NaOH in the solution?

Options:

A) Molarity: 2.675 M; Molality: 2.778 m; Mole Fraction: 0.0476

B) Molarity: 2.500 M; Molality: 2.500 m; Mole Fraction: 0.0500

C) Molarity: 1.070 M; Molality: 1.000 m; Mole Fraction: 0.1000

D) Molarity: 2.778 M; Molality: 2.675 m; Mole Fraction: 0.0450

37 minutes ago | [YT] | 0

CRACKNEETPhysics

Are you looking to master Electromagnetic Waves for your Class 12 Physics exams? Don't miss this comprehensive 4-Class Series on my channel, CRACKNEETPhysics-Selection Walla!I

In these sessions, we dive deep into the complete chapter of EM Waves, covering:
Detailed Theory: Understand the core concepts from Displacement Current to the EM Spectrum based on the NCERT syllabus.

Solved Numericals: Step-by-step solutions for calculation-based problems involving I{d}, energy density, and wave equations.MCQs & Practice:

Sharpen your objective-solving skills for NEET and JEE Mains.Reasoning & Assertion:

Master the conceptual questions that often trip up students in CBSE and competitive exams.

Whether you're aiming for a top rank in NEET/JEE or looking to ace your Board exams, these classes provide the clarity and practice you need.👉 Watch now and secure your marks in EM Waves!

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1 hour ago | [YT] | 0

CRACKNEETPhysics

The magnetic field in four regions I, II, III, and IV is given as follows:

I. B_y = B_0 sin(kz)

II. B_y = B_0 cos(kz)

III. B_y = B_0 sin(kz - ωt)

IV. B_y = B_0 sin(kz) + B_0 cos(kz)

In which of these regions will an electromagnetic wave exist?

(A) IV
(B) I
(C) III
(D) II

Answer :- https://youtu.be/w7YkgSqoRxw

2 hours ago | [YT] | 0

CRACKNEETPhysics

In a parallel plate capacitor connected to an AC source where the charge is varying as q = q₀ cos(ωt), which of the following statements correctly describes the relationship between the Conduction Current (I_c) in the wires and the Displacement Current (I_d) between the plates?

(A) I_d is always zero because there is no physical flow of electrons between the capacitor plates.


(B) I_c and I_d are equal in magnitude at all times to maintain the continuity of current.

(C) I_d exists only when the capacitor is fully charged and the conduction current stops.

(D) I_c is proportional to cos(ωt), while I_d is proportional to sin(ωt), making them unequal.

Answer https://youtu.be/hucnXCieopE

2 hours ago | [YT] | 0

CRACKNEETPhysics

Assertion (A): The magnetic field produced in the region between the plates of a charging capacitor is identical in nature to the magnetic field produced around a current-carrying wire.

Reason (R): The magnetic field between the capacitor plates is generated by the physical flow of electrons across the vacuum gap between the plates.

Choose the Correct Option:


(A) Both (A) and (R) are true, and (R) is the correct explanation of (A).

(B) Both (A) and (R) are true, but (R) is NOT the correct explanation of (A).

(C) (A) is true, but (R) is false.

(D) (A) is false, but (R) is true.

Answer: youtube.com/live/VYvYi4kTziM

2 hours ago | [YT] | 0

CRACKNEETPhysics

A beam of light (Electromagnetic Wave) is traveling through space. Which of the following statements about its Intensity (I) is INCORRECT?

(A) The Intensity of the wave is a constant value that does not change even if the beam is focused into a smaller area.

(B) The total average energy density of the wave is the sum of the energy densities of the electric field and the magnetic field.

(C) If the amplitude of the electric field is doubled, the Intensity of the wave becomes four times its original value.

(D) In an electromagnetic wave, the electric field and the magnetic field contribute equally to the total intensity.


Answer https://youtu.be/wGW8Z4MkFCI

2 hours ago | [YT] | 0

CRACKNEETPhysics

🧠 Selection Walla Challenge: Displacement Current (Id)
Question: Which of the following statements regarding Displacement Current (Id) is INCORRECT?

(A) Displacement current arises due to a time-varying electric flux between the plates of a capacitor.


(B) Like conduction current, displacement current is a source of a magnetic field and satisfies the principle of continuity.


(C) In the region between the plates of a charging capacitor, both conduction current (Ic) and displacement current (Id) are present and equal in magnitude.


(D) The displacement current exists even in a vacuum where no actual charge carriers (electrons or ions) are present.

3 hours ago | [YT] | 1

CRACKNEETPhysics

Question: Which of the following statements regarding the intensity of an electromagnetic wave is INCORRECT?

(A) The intensity of an electromagnetic wave represents the total power transferred per unit area by the wave.

(B) In an electromagnetic wave, the energy is stored predominantly in the electric field, with the magnetic field contributing negligible intensity.

(C) The average intensity of an electromagnetic wave is mathematically expressed as the product of the average energy density and the speed of light (I = u_avg × c).


(D) Average intensity is used in practical measurements because the instantaneous intensity fluctuates sinusoidally over time due to the nature of E and B fields.

Answer : open.substack.com/pub/crackneetphysics/p/neet-and-…

3 hours ago | [YT] | 0

CRACKNEETPhysics

If E and B represent electric and magnetic field vectors of the electromagnetic wave, the direction of propagation of electromagnetic wave is along:

(a) E
(b) B
(c) B × E
(d) E × B

Answer https://youtu.be/TEUYci295XM?si=PjAlT...

3 hours ago | [YT] | 0