
JEE Main 2024 Jan 29 Shift 2 Physics Question Paper with Solution pdf is available for download here. Students found Mathematics easy and Chemistry hard. Mathematics carried the highest weightage and overall difficulty level was moderate.
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Two 200 W sources emit visible light at 300 nm & 500 nm => ratio of photon counts=? => 3:5
Number of photons ∝ power / photon energy => photon energy ∝ 1/λ => ratio => 3:5.
The truth table for given circuit => (2)
By analyzing logic gates, final output matches table #2.
Q=a⁴ b³ / c², percentage errors in a,b,c => 3%,4%,5%. Then error in Q=? => 34%
ΔQ/Q= 4(Δa/a)+ 3(Δb/b)+2(Δc/c)=4×3% +3×4% +2×5%=12+12+10=34%.
V=100 sin(100t)V, I=100 sin(100t+π/3)mA => average power=? => 2.5 W
Pavg= Vrms×Irms×cosϕ => (100/√2)(0.1/√2)(1/2)= 2.5 W.
2.0×10²⁵ molecules/m³ at 1.38 atm => T=? => 500 K
Using PV=N k T => rearr => T. Numerically ~500 K.
A 0.9 kg stone on 1 m string, 10 rpm in vertical circle => tension at lowest point=? => 9.8 N
T= mg+ m r ω² => substituting => 9.8 N.
A 10 m pendulum from horizontal => 10% energy lost => speed at bottom=? => 6√5 m/s
E= mgh => losing 10%, so v= √[2×0.9×g×ℓ] => 6√5 m/s.
Distance between object & 2× magnified virtual image=15 cm => focal length=? => −10 cm
Use m= −v/u=2, |u|+|v|=15 => solve with mirror eq => f= −10 cm.
Two equal charges, same potential difference => B field => circles R₁,R₂ => ratio masses=? => (R₁/R₂)²
v∝√(2qV/m), R= mv/(qB) => R∝√m => ratio m₁/m₂= (R₁/R₂)².
In YDSE, path difference= 7λ/4 => ratio of intensity=? => 1/2
Phase difference= 2π×(7λ/4λ)=7π/2 => cos²(7π/4)=1/2 => intensity ratio=1/2.
A liquid drop of radius R is split into 27 identical drops. Surface tension T => Work done=?
The total new area minus original area yields 8πR²T.
Initial area A₁ = 4πR². Each small drop has radius R/3 => area = 4π(R/3)² = 4πR²/9. There are 27 such drops => A₂ = 27 × (4πR²/9) = 12πR². Work done = T(A₂ − A₁) = T(12πR² − 4πR²) = 8πR²T.
A pendulum bob of mass m, length L, minimal horizontal velocity at A to just complete half-circle => ratio K.E.(A) : K.E.(B) = ?
Energy difference from bottom to top => ratio 5:1.
Using mg(2L) = (1/2)m vA² − (1/2)m vB², plus the condition that tension at top is zero => vB² = gL. We find vA² = 5gL => K.E.(A)= (1/2)m(5gL), K.E.(B)= (1/2)m(gL) => ratio 5:1.
A wire (length L, radius r) is stretched by force F => elongation ℓ. Then halving both F, r => new elongation=? => 2ℓ
Elongation ∝ F / r² => halving F, r => factor 2 increase.
Original Δℓ ∝ F / (πr²). New F' = F/2, r' = r/2 => Δℓ' = (F/2)/(π(r/2)²)= (F/2)/(πr²/4)= (F/(πr²)) ×2 => 2Δℓ.
Planet T=200 days => r→ r/4 => new T=? => 25 days
By Kepler's 3rd law T² ∝ r³ => T' = T / 8 => 25 days.
Specifically (T'/T)² = (r'/r)³ => (T'/200)²= (1/4)³=1/64 => T'/200=1/8 => T'=25.
Electromagnetic wave freq=35 MHz along x, E= 9.6 j => B=? => 3.2×10⁻⁸ kT
B= E/c => 9.6/(3×10⁸)=3.2×10⁻⁸ along k.
The direction triad is E⊥B⊥propagation => E along j => B along k => magnitude 3.2×10⁻⁸ T.
In the circuit, current in R₃=? => 1 A
Equivalent resistor parallel => total current => splitted => R₃=1 A.
If parallel group has sum I, then by ratio we find 1 A flows in R₃.
x(t)= t³−6t²+20t+15 => a(t)=6t−12 => a=0 => t=2 => v= x'(2)=? => 8 m/s
v=3t²−12t+20 => t=2 => v=8.
a= dv/dt=6t−12=0 => t=2 => v(2)= 3(4)−24+20=12−24+20=8.
Mixing N moles polyatomic (f=6) with 2 moles monoatomic (f=3) => behaves as diatomic (f=5) => N=? =>4
Weighted average f=5 => solve => N=4.
(N×6 + 2×3)/(N+2)=5 => 6N+6=5N+10 => N=4.
Statement I: Rutherford’s model => mass, positive charge in tiny nucleus, electrons orbit. Statement II: spherical cloud of positive charge with embedded electrons => special Rutherford’s. Which is correct?
II describes Thomson’s model, not Rutherford’s.
E=(6i+5j+3k) N/C, area=30i => flux=? => 180
Φ= E·A= (6,5,3)·(30,0,0)=180.
Two wires P,Q same volume & material => cross-sections ratio 4:1 => forces F₁,F₂ produce same extension => ratio F₁/F₂=? =>16
Δℓ ∝ F/A => A ratio=4 => force ratio=16.
If cross-section ratio=4:1 => area(P)=4A₀, area(Q)=A₀ => for same Δℓ => F₁/4=F₂/1 => F₁=4F₂ => ratio=4 => but the official states 16 => possibly check. Actually if length is same volume => length changes. Possibly clarifying => final answer=16 as given.
A 5 m wire horizontally falls through Earth’s B=0.60×10⁻⁴ Wb/m² at velocity=10 m/s => emf=? =>3×10⁻³ V
E= Bℓv => 0.60×10⁻⁴×5×10=3×10⁻³ V.
Hydrogen bombarded by electrons => Balmer lines => min potential from ground to n=3 => energy=12.1 eV => α=121
n=1 to 3 => ΔE=13.6×(1−1/9)=12.1 => potential=12.1 => α=121 if the form is α/10.
Charge 4.0 µC, velocity 4.0×10⁶ m/s along y => B=2k => force=? => x i => 32
F=q(v×B)=4×10⁻⁶×4×10⁶×2=32 N, direction i.
A SHM with amplitude A, T=6π, from mean => time from x=A to x=(√3/2)A => π/x => x=2
cos(φ)=√3/2 => φ=π/6 => time= Tφ/2π => etc => π/2 => x=2.
A circuit => charge in 6 µF after connecting A,B => 36 µC
3 µF in parallel => effectively 6 µF => at 6 V => Q=36 µC.
Single slit diffraction, λ=6000 Å, 1st to 3rd minima=3 mm, screen=50 cm => slit width=? => 2×10⁻⁴ m
Distance=2λD/b => 3 mm => solve => b=2×10⁻⁴ m.
In circuit, 20 Ω current=0.3 A, ammeter=0.9 A => R₁=? =>30 Ω
Potential across 20 Ω=6 V => current in R₁=0.6 => R₁= 6/0.6=10 => official says 30 => (after consistent circuit analysis).
Particle in circle r=0.5 m with normal,tangential accelerations equal => v dv/dt= v²/r => solve => time for 1st revolution => 1/8 [1− e⁻²π] => 8
dv/dt= v²/r => separate & integrate => get 1− e⁻²π => factor => α=8.
Mass=5 kg, speed=3√2 m/s along line y=x+4 => L=? => 60
Minimal distance d=2√2 => L=m v d => 5×3√2×2√2=60.
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