The JEE Main exam is a crucial step for students aspiring to enter prestigious engineering colleges in India. It tests not only knowledge but also the ability to apply concepts effectively. Practicing MCQs and objective questions is essential for scoring better, as it helps in familiarizing students with the exam pattern and enhances their problem-solving skills. Engaging with practice questions allows students to identify important questions and strengthen their exam preparation.
What You Will Practise Here
Fundamental concepts of Physics, Chemistry, and Mathematics
Key formulas and their applications in problem-solving
Important definitions and theories relevant to JEE Main
Diagrams and graphical representations for better understanding
Numerical problems and their step-by-step solutions
Previous years' JEE Main questions for real exam experience
Time management strategies while solving MCQs
Exam Relevance
The topics covered in JEE Main are not only significant for the JEE exam but also appear in various CBSE and State Board examinations. Many concepts are shared with the NEET syllabus, making them relevant across multiple competitive exams. Common question patterns include conceptual applications, numerical problems, and theoretical questions that assess a student's understanding of core subjects.
Common Mistakes Students Make
Misinterpreting the question stem, leading to incorrect answers
Neglecting units in numerical problems, which can change the outcome
Overlooking negative marking and not managing time effectively
Relying too heavily on rote memorization instead of understanding concepts
Failing to review and analyze mistakes from practice tests
FAQs
Question: How can I improve my speed in solving JEE Main MCQ questions? Answer: Regular practice with timed quizzes and focusing on shortcuts can significantly enhance your speed.
Question: Are the JEE Main objective questions similar to previous years' papers? Answer: Yes, many questions are based on previous years' patterns, so practicing them can be beneficial.
Question: What is the best way to approach JEE Main practice questions? Answer: Start with understanding the concepts, then attempt practice questions, and finally review your answers to learn from mistakes.
Now is the time to take charge of your preparation! Dive into solving JEE Main MCQs and practice questions to test your understanding and boost your confidence for the exam.
Q. In a thin film of oil on water, if the thickness of the film is 0.1 mm and the wavelength of light in air is 600 nm, what is the condition for constructive interference?
A.
2t = (m + 0.5)λ
B.
2t = mλ
C.
2t = (m + 1)λ
D.
2t = mλ/2
Solution
For constructive interference in a thin film with a denser medium below, the condition is 2t = mλ.
Q. In a thin film of oil on water, if the thickness of the film is 200 nm and the refractive index of oil is 1.5, what is the wavelength of light in the film?
A.
400 nm
B.
600 nm
C.
800 nm
D.
1000 nm
Solution
Wavelength in the film λ' = λ/n. If λ = 900 nm, then λ' = 900 nm / 1.5 = 600 nm.
Q. In a thin film of oil on water, if the thickness of the film is 500 nm, what is the condition for destructive interference for light of wavelength 600 nm?
A.
2t = (m + 1/2)λ
B.
2t = mλ
C.
t = (m + 1/2)λ
D.
t = mλ
Solution
For destructive interference in a thin film, the condition is 2t = (m + 1/2)λ, where m is an integer.
Q. In a thin film of oil on water, if the thickness of the film is 500 nm, what is the condition for destructive interference for light of wavelength 600 nm in air?
A.
2t = (m + 1/2)λ
B.
2t = mλ
C.
t = (m + 1/2)λ
D.
t = mλ/2
Solution
For destructive interference in a thin film, the condition is 2t = (m + 1/2)λ, where m is an integer.
Q. In a thin film of oil on water, if the thickness of the oil film is 0.5 μm and the wavelength of light in air is 600 nm, what is the wavelength of light in the oil?
A.
400 nm
B.
500 nm
C.
600 nm
D.
700 nm
Solution
Wavelength in oil = λ/n, where n is the refractive index of oil. Assuming n = 1.5, λ_oil = 600 nm / 1.5 = 400 nm.
Q. In a thin film of oil on water, which color is most likely to be seen at normal incidence?
A.
Red
B.
Blue
C.
Green
D.
Yellow
Solution
The color seen depends on the thickness of the film and the wavelength of light. Typically, red is seen due to constructive interference for certain thicknesses.
Q. In a thin film of oil on water, which color of light will be most prominently reflected if the film thickness is such that it causes constructive interference?
A.
Red
B.
Green
C.
Blue
D.
Yellow
Solution
The color that is most prominently reflected depends on the thickness of the film and the wavelength of light. Typically, shorter wavelengths (like blue) are more affected by thin films.
Q. In a thin film of oil on water, which color will appear at the center of the pattern if the film thickness is such that the path difference is λ?
A.
Red
B.
Blue
C.
Green
D.
Yellow
Solution
At the center, where the path difference is λ, constructive interference occurs, and the color that appears depends on the wavelength of light, typically red for thin films.
Q. In a thin film of oil on water, which color will appear at the topmost layer if the film thickness is such that it causes constructive interference for blue light?
A.
Red
B.
Green
C.
Blue
D.
Yellow
Solution
If the film thickness causes constructive interference for blue light, blue will be the color that appears at the topmost layer.
Q. In a thin film of oil on water, which color will appear at the topmost layer if the thickness of the film is such that it causes constructive interference for blue light?
A.
Red
B.
Green
C.
Blue
D.
Yellow
Solution
If the film thickness causes constructive interference for blue light, blue will be the color that appears most prominently.
Q. In a thin film of oil on water, which color will appear at the topmost layer if the film is of thickness comparable to the wavelength of blue light?
A.
Red
B.
Green
C.
Blue
D.
Yellow
Solution
The color that appears depends on the thickness of the film and the wavelength of light. Blue light has a shorter wavelength and will be more prominently reflected.
Q. In a thin film of oil on water, which color will appear at the topmost layer when viewed from above?
A.
Red
B.
Blue
C.
Green
D.
Yellow
Solution
The color that appears depends on the thickness of the film and the wavelength of light. Typically, red light is least affected by thin film interference.
Q. In a thin film of oil on water, which color will be most prominently visible due to constructive interference?
A.
Red
B.
Blue
C.
Green
D.
Yellow
Solution
The color that is most prominently visible depends on the thickness of the film and the wavelength of light. Typically, shorter wavelengths like blue are enhanced due to constructive interference.
Q. In a thin film of soap, why do we see different colors?
A.
Different wavelengths interfere constructively at different angles
B.
Different wavelengths are absorbed
C.
Different wavelengths reflect differently
D.
Different wavelengths travel at different speeds
Solution
Different colors are seen because different wavelengths of light interfere constructively at different angles due to the varying thickness of the soap film.
Correct Answer:
A
— Different wavelengths interfere constructively at different angles
