JEE Main DPP 21 December 2024: Daily practice problems for 2025 aspirants

JEE Main DPP 21 December 2024: JEE Main Session 1 2025 will take place from January 22 to 31. Applicants preparing for the exam must focus on practising the JEE Main sample papers. Hence, here are some daily practice questions with answers for JEE Main DPP 21 December  2024, including five questions from each subject: Mathematics, Physics, and Chemistry.

Also Read | NEET Daily Practice Questions 21 December 2024: DPP for 2025 aspirants

JEE Main DPP 21 December 2024: Physics

Candidates can check out the JEE Main DPP 21 December  2024 daily practice problems for 2025 aspirants from the Physics section:

Question 1: A proton, a deuteron and an a-particle with same kinetic energy enter into a uniform magnetic field at right angle to magnetic field. The ratio of the radii of their respective circular paths is :

(A) 1:(2)^½:(2)^½

(B) 1:1:(2)^½

(C) (2)^½:1:1

(D) 1:(2)^½:1

Answer (C)

Question 2: Two massless springs with spring constant 2 k and 9 k, carry 50 g and 100 g masses at their free ends. These two masses oscillate vertically such that their maximum velocities are equal. Then, the ratio of their respective amplitude will be

(A) 1 : 2

(B) 3 : 2

(C) 3 : 1

(D) 2 : 3

Answer (B)

Question 3: What will be the most suitable combination of three resistors A = 2 ohms, B = 4 ohms C = 6 ohms so that (22/3)ohms is equivalent resistance of combination?

(A)  Parallel combination of A and C connected in series with B.

(B)  Parallel combination of A and B connected in series with C

(C) Series combination of A and C connected in parallel with B.

(D) Series combination of B and C connected in parallel with A.

Answer (B)

Question 4: Given below are two statements:

Statement-I : The reactance of an ac circuit is zero. It is possible that the circuit contains a capacitor and an inductor.

Statement-II : In a circuit, the average power delivered by the source never becomes zero.

In the light of the above statements, choose the correct answer from the options given below.

(A) Both Statement I and Statement II are true

(B) Both Statement I and Statement II are false

(C) Statement I is true but Statement II is false

(D) Statement I is false but Statement II is true

Answer (C)

Question 5: The soft-iron is a suitable material for making an electromagnet. This is because soft-iron has

(A) Low coercivity and high retentivity

(B) Low coercivity and low permeability

(C) High permeability and low retentivity

(D) High permeability and high retentivity

Answer (C)

JEE Main DPP 21 December 2024: Chemistry

Candidates can check out the JEE Main DPP 21 December  2024 daily practice problems for 2025 aspirants from the Chemistry section:

Question 1: Which one of the following compounds is used as a chemical in certain type of fire extinguishers?

(1)  Baking soda

(2)  Soda ash

(3)  Washing soda

(4)  Caustic Soda

Answer (A)

Question 2: PCl5 is well known, but NCl5 is not. Because,

(1)  nitrogen is less reactive than phosphorous

(2)  nitrogen doesn’t have d-orbitals in its valence shell.

(3) catenation tendency is weaker in nitrogen than phosphorus.

(4) size of phosphorus is larger than nitrogen

Answer (B)

Question 3: Transition metal complex with highest value of crystal field splitting (D0) will be

(A)   [Cr(H2O)6]3+

(B)   [Mo(H2O)6]3+

(C)   [Fe(H2O)6]3+

(D)  [Os(H2O)6]3+

Answer (D)

Question 4: Some gases are responsible for heating the atmosphere (green house effect). Identify from the following the gaseous species which does not cause it.

(A)  CH4

(B)  O3

(C)  H2O

(D)  N2

Answer (D)

Question 5: Given below are two statements.

Statement I: The presence of weaker p-bonds make alkenes less stable than alkanes.

Statement II: The strength of the double bond is greater than that of carbon-carbon single bond.

In the light of the above statements, choose the correct answer from the options given below.

(A)  Both Statement I and Statement II are correct.

(B)  Both Statement I and Statement II are incorrect.

(C)  Statement I is correct but Statement II is incorrect.

(D)  Statement I is incorrect but Statement II is correct.

Answer (A)

JEE Main DPP 21 December 2024: Mathematics

Candidates can check out the JEE Main DPP 21 December 2024 daily practice problems for 2025 aspirants from Maths section:

Problem 1: If nPr = nPr + 1 and nCr = nCr – 1¢ then the value of r is equal to

1)  4

(2) 3

(3) 2

(4) 1

Solution (3)

Problem 2: The first of the two samples in the group has 100 items with mean 15 and standard deviation 3. If the whole group has 250 items with mean 15.6 and standard deviation  (13.44)^½, then the standard deviation of the second sample is

(1) 5

(2) 6

(3) 4

(4) 8

Solution (3)

Problem 3: If a tangent to the ellipse x2 + 4y2 = 4 meets the tangents at the extremities of its major axis at B and C, then the circle with BC as diameter passes through the point

(1) (-1,1)

(2) ((3)^½, 0)

(3) (1,1)

(4) ((2)^,0)

Solution (2)

Problem 4: If a + b + c = 1, ab + bc + ca = 2 and abc = 3, then the value of a4 + b4 + c4 is equal to ..

(1) 12

(2) 13

(3) 14

(4) 15

Solution (2)

Problem 5: A fair coin is tossed n-times such that the probability of getting at least one head is at least 0.9. Then the minimum value of n is

(1) 1

(2) 2

(3) 3

(4) 4

Solution (4)

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