Which of these is an example of an aromatic compound?
A. Cyclohexane
B. Benzene
C. Cyclohexene
D. 1,3-cyclohexadiene
Correct Answer: B Benzene (CH) is aromatic with delocalized 6pi electrons.
Q2. Chemistry
The oxide that turns red litmus blue is:
A. CO
B. SO
C. NaO
D. PO
Correct Answer: C NaO is basic oxide -> turns red litmus blue. CO, SO, PO are acidic.
Q3. Physics
The refractive index of a medium is 1.5. Speed of light in this medium is:
A. 3 x 10 m/s
B. 2 x 10 m/s
C. 4.5 x 10 m/s
D. 1.5 x 10 m/s
Correct Answer: B v = c/n = 3x10/1.5 = 2x10 m/s.
Q4. Physics
A particle of mass m is released from rest at a height h above a horizontal surface. If it falls under gravity, and experiences a resistive force proportional to its velocity (F_r = -kv), where k is a positive constant, what is the terminal velocity it approaches?
A. mg/k
B. sqrt(2gh)
C. k/mg
D. mgh/k
Correct Answer: A Terminal velocity is reached when the net force on the particle is zero. The forces acting on the particle are gravity (mg downwards) and the resistive force (-kv upwards). Thus, mg - kv_t = 0, which gives v_t = mg/k.
Q5. Physics
The dimension of Planck's constant is same as:
A. Energy
B. Angular momentum
C. Force
D. Power
Correct Answer: B h = E/ -> [ML^2T] same as angular momentum.
Q6. Chemistry
Which of the following is an isotope of hydrogen?
A. Protium
B. Deuterium
C. Tritium
D. All of these
Correct Answer: D Protium (H), Deuterium (^2H), and Tritium (H) are all isotopes of hydrogen.
Q7. Biology
Which organ is responsible for blood filtration?
A. Liver
B. Kidney
C. Heart
D. Lungs
Correct Answer: B Kidneys filter blood through nephrons, removing waste and excess water to form urine.
Q8. Biology
The pigment responsible for skin color is:
A. Chlorophyll
B. Haemoglobin
C. Melanin
D. Carotene
Correct Answer: C Melanin produced by melanocytes determines skin, hair, and eye color.
Q9. Chemistry
The catalyst used in the contact process for HSO is:
A. VO
B. Fe
C. Ni
D. Pt
Correct Answer: A Contact process uses VO (vanadium pentoxide) as catalyst.
Q10. Physics
A convex lens of focal length 20 cm is placed in contact with a concave lens of focal length 30 cm. The focal length of the combination is:
A.
B.
C.
D.
Correct Answer: C For a combination of thin lenses in contact, the reciprocal of the equivalent focal length (F) is given by 1/F = 1/f + 1/f. Given f = +20 cm (convex lens) and f = -30 cm (concave lens). So, 1/F = 1/20 + 1/(-30) = 1/20 - 1/30. To combine, find a common denominator, which is 60. 1/F = (3/60) - (2/60) = 1/60. Therefore, F = +60 cm.
Q11. Physics
A lens of power +2 D has focal length:
A. 0.5 m
B. 0.5 m
C. 2 m
D. 5 m
Correct Answer: B f = 1/P = 1/2 = 0.5 m. Positive power -> convex lens.
Q12. Physics
The de Broglie wavelength of an electron accelerated through a potential difference V is given by:
A. h / sqrt(mV)
B. h / sqrt(2meV)
C. h / sqrt(2mVe)
D. h / sqrt(V/2me)
Correct Answer: B When an electron is accelerated through a potential difference V, it gains kinetic energy KE = eV. The kinetic energy is also given by KE = p^2 / 2m, where p is the momentum and m is the mass of the electron. Therefore, p = sqrt(2mKE) = sqrt(2meV). The de Broglie wavelength is given by = h/p. Substituting the expression for p, we get = h / sqrt(2meV).
Q13. Physics
The energy equivalent of 1 amu is:
A. 931 eV
B. 931 MeV
C. 931 keV
D. 931 J
Correct Answer: B 1 amu = 931.5 MeV/c^2.
Q14. Chemistry
What is the type of bond that occurs between two atoms with a large difference in electronegativity?
A. Covalent bond
B. Ionic bond
C. Hydrogen bond
D. Van der Waals bond
Correct Answer: B Ionic bonds occur between two atoms with a large difference in electronegativity, resulting in the transfer of electrons and the formation of ions.
Q15. Biology
The process of cell division for growth is:
A. Meiosis
B. Mitosis
C. Binary fission
D. Budding
Correct Answer: B Mitosis produces identical daughter cells for growth and repair.