Q211. A force defined by; $F = \alpha t^2 + \beta t$ acts on a particle at a given time $t.$ The factor which is dimensionless, if $\alpha$ and $\beta$ are constants, is:
- $\alpha t / \beta$
- $\alpha \beta t$
- $\alpha \beta / t$
- $\beta t / \alpha$
Explanation:
Hint: Recall the principle of homogeneity of dimensions.
Step: Find the dimensionless quantity.
According to the principle of homogeneity of dimensions, the dimensions of LHS = dimensions of RHS i.e.,
Therefore, the dimensionless quantity is .
Hence, option (1) is the correct answer.
#454992
Exam: NEET – 2024
Q212. In a vernier callipers, $(N+1)$ divisions of the vernier scale coincide with $N$ divisions of the main scale. If $1$ $\text{MSD}$ represents $0.1~\text{mm}$ , the vernier constant (in $\text{cm}$ ) is:
- $\dfrac{1}{100(N+1)}$
- $100N$
- $10(N+1)$
- $\dfrac{1}{10 N}$
Explanation:
Hint:
Step: Find the vernier constant () in cm.
It is given in the question that
The vernier constant or Least count is given by;
Hence, option (1) is the correct answer.
#454980
Exam: NEET – 2024
Q213. The quantities which have the same dimensions as those of solid angle are:
- stress and angle
- strain and arc
- angular speed and stress
- strain and angle
Explanation:
Hint: Recall the dimensions of the given quantities.
Step: Find the quantities which have the same dimensions as those of solid angles.
The expression of the solid angle is given by;
Therefore, the solid angle is a dimensionless quantity.
The dimensions of strain are given by;
The dimensions of the angle are given by;
Therefore, strain and angle are both dimensionless quantities.
Hence, option (4) is the correct answer.
We see that your answer is incorrect, Please mention reason from these.
Silly Mistake
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Exam: NEET – 2024
Q214. Silly Mistake
Conceptual Mistake
Other Reason
#535138
Exam: NEET – 2025
Q215. Each side of a metallic cube of mass $5.580$ kg is measured to be $9.0$ cm. Keeping the significant figures in view, the density of the material of the cube can be best expressed as $X \times10^3 ~\text{kg m}^{-3},$ where the value of $X$ is:
- $7.654$
- $7.7$
- $7.65$
- $7.6$
Explanation:
Hint: If the preceding digit is even, the insignificant digit is simply dropped and, if it is odd, the preceding digit is raised by .
Step: Find the density of the material in correct order.
The density of the material is given by;
The volume of the metallic cube is given by;
The mass of the metallic cube is given by;
The density of the metallic cube is given by;
In multiplication or division, the final result should retain as many significant figures as are there in the original number with the least significant figures. So the final answer should be in significant figures.
According to the rule of rounding off, if the preceding digit is even, the insignificant digit is simply dropped and, if it is odd, the preceding digit is raised by .
Therefore, the final density of the metallic cube is
Hence, option (4) is the correct answer.
We see that your answer is incorrect, Please mention reason from these.
Silly Mistake
Conceptual Mistake
Other Reason
#592781
Exam: NEET – 2026
Q216. In vernier callipers, $20$ VSD coincides with $16$ MSD (each division of length $1$ mm). The least count of the vernier callipers is:
- $0.01$ cm
- $0.1$ cm
- $0.02$ cm
- $0.2$ cm
Explanation:
Hint: LC MSD VSD
Step: Find the least count of the vernier callipers.
The least count of the vernier calliper is given by;
Given in the question;
Hence, option (3) is the correct answer.
#592766
Exam: NEET – 2026
Q217. The speed of light in vacuum is taken as unity. If light takes $6$ min $40$ s to reach the Earth from the Sun, the distance between the Sun and the Earth in a new unit is:
- $3 \times 10^8$
- $3 \times 10^{10}$
- $400$
- $500$
Explanation:
Hint: Convert time into seconds; since speed distance equals time directly.
Step: Find the distance between the Sun and the Earth in a new unit.
The Speed of light is given as , so distance covered is given by time taken.
The time taken by the light is min s = .
The distance between the sun and earth in new unit is
Hence, option (3) is the correct answer.
#592764
Exam: NEET – 2026
Q218. Reagents that can be used to convert alcohols to carboxylic acids are:
(A) CrO3 – H2SO4
(B) K2Cr2O7 + H2SO4
(C) KMnO4 + KOH/H3O+
(D) Cu, 573 K
(E) CrO3+ (CH3CO)2O
Choose the most appropriate answer from the options given below:
- (B), (C) and (D) only
- (B), (D) and (E) only
- (A), (B) and (C) only
- (A), (B) and (E) only
Explanation:
Hint: Strong oxidizing agent oxidized alcohol into carboxylic acid.
When primary alcohol reacts with a strong oxidizing agent then an acid is formed as a product. When primary alcohol reacts with the mild oxidizing agent then aldehyde is formed as a product.
Here, CrO3 – H2SO4, K2Cr2O7 + H2SO4, and KMnO4 + KOH/H3O+ are strong oxidizing agents thus, converts alcohol into acid.
But Cu, 573 K, and CrO3+ (CH3CO)2O are the weak oxidizing agent and reduce primary alcohol to aldehyde.
Thus, option third is the correct answer.
#368236
Exam: NEET – 2023
Q219. Consider the following reaction:
Identify products A and B:
Explanation:
Hint: One of the product is phenol
When ether reacts with HI then cleavage of the ether bond takes place. The mechanism of the given compound is as follows:
Here, phenol and benzyl iodide are formed as products.
The correct answer is option fourth.
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Exam: NEET – 2023
Q220. Which amongst the following will be most readily dehydrated under acidic conditions?
Explanation:
Hint: Rate of dehydration reaction depends on the stability of carbocation
The rate of dehydration reaction depends on the stability of carbocation. The stability of carbocation is as follows:
3o > 2o > 1o
The carbocation formed by the given compound is as follows:
The carbocation formed in (iii) is the most stable because in (i), (iii), and (iv) carbocation is unstable because of -I effect of NO2. Thus, option third is the correct answer.
#367000
Exam: NEET – 2023
