Undergraduate
Q. The half-life of a first-order reaction is independent of the initial concentration of the reactant. What is the formula for the half-life (t1/2) of a first-order reaction? (2020)
A.
t1/2 = 0.693/k
B.
t1/2 = k/0.693
C.
t1/2 = 1/k
D.
t1/2 = k/1
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Solution
The half-life of a first-order reaction is given by the formula t1/2 = 0.693/k, where k is the rate constant.
Correct Answer: A — t1/2 = 0.693/k
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Q. The heat capacity at constant volume (Cv) is defined as: (2022)
A.
The amount of heat required to raise the temperature of a substance by 1°C at constant pressure.
B.
The amount of heat required to raise the temperature of a substance by 1°C at constant volume.
C.
The total heat content of a substance.
D.
The heat required to change the phase of a substance.
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Solution
The heat capacity at constant volume (Cv) is defined as the amount of heat required to raise the temperature of a substance by 1°C at constant volume.
Correct Answer: B — The amount of heat required to raise the temperature of a substance by 1°C at constant volume.
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Q. The Langmuir isotherm assumes that adsorption occurs at specific sites on the surface. What is the maximum coverage called? (2021)
A.
Saturation
B.
Monolayer
C.
Multilayer
D.
Equilibrium
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Solution
In the Langmuir isotherm, the maximum coverage of adsorbate on the adsorbent is referred to as a monolayer.
Correct Answer: B — Monolayer
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Q. The Langmuir isotherm assumes that adsorption occurs at specific sites on the surface. What does this imply? (2020)
A.
Adsorption is uniform.
B.
Adsorption is multilayered.
C.
Adsorption is monolayered.
D.
Adsorption is temperature dependent.
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Solution
The Langmuir isotherm assumes that adsorption occurs at specific sites, leading to a monolayer coverage of the adsorbate.
Correct Answer: C — Adsorption is monolayered.
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Q. The magnetic field inside a long solenoid is given by which of the following expressions? (2020)
A.
μ₀nI
B.
μ₀I/n
C.
nI/μ₀
D.
I/μ₀n
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Solution
The magnetic field (B) inside a long solenoid is given by B = μ₀nI, where n is the number of turns per unit length and I is the current.
Correct Answer: A — μ₀nI
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Q. The magnetic field lines inside a bar magnet are directed from: (2019)
A.
North to South
B.
South to North
C.
East to West
D.
West to East
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Solution
The magnetic field lines inside a bar magnet are directed from the North pole to the South pole.
Correct Answer: A — North to South
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Q. The maximum displacement of a wave from its rest position is called what? (2022)
A.
Amplitude
B.
Wavelength
C.
Frequency
D.
Period
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Solution
The maximum displacement from the rest position is defined as the amplitude of the wave.
Correct Answer: A — Amplitude
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Q. The potential energy stored in a capacitor is given by which of the following formulas? (2020)
A.
1/2 CV^2
B.
CV
C.
Q^2/2C
D.
1/2 QV
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Solution
The potential energy (U) stored in a capacitor is given by U = 1/2 CV^2.
Correct Answer: A — 1/2 CV^2
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Q. The pressure of an ideal gas is directly proportional to its temperature when: (2022)
A.
Volume is constant
B.
Number of moles is constant
C.
Both volume and number of moles are constant
D.
None of the above
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Solution
According to Gay-Lussac's law, the pressure of an ideal gas is directly proportional to its temperature when the volume is held constant.
Correct Answer: A — Volume is constant
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Q. The rate constant of a reaction is affected by which of the following? (2023)
A.
Nature of the reactants
B.
Temperature
C.
Catalysts
D.
All of the above
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Solution
The rate constant of a reaction is affected by the nature of the reactants, temperature, and the presence of catalysts.
Correct Answer: D — All of the above
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Q. The restoring force in simple harmonic motion is directly proportional to what? (2022)
A.
Displacement
B.
Velocity
C.
Acceleration
D.
Mass
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Solution
The restoring force (F) is directly proportional to the displacement (x) and acts in the opposite direction, F = -kx.
Correct Answer: A — Displacement
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Q. The scientific study of classification is known as: (2022)
A.
Taxonomy
B.
Morphology
C.
Anatomy
D.
Ecology
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Solution
Taxonomy is the scientific study of classification of organisms.
Correct Answer: A — Taxonomy
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Q. The specific heat capacity of a substance is defined as: (2023)
A.
The amount of heat required to raise the temperature by 1 degree Celsius
B.
The amount of heat required to change the phase of a substance
C.
The heat required to raise the temperature of 1 kg of the substance by 1 degree Celsius
D.
The heat required to raise the temperature of 1 mole of the substance by 1 degree Celsius
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Solution
The specific heat capacity is defined as the amount of heat required to raise the temperature of 1 kg of the substance by 1 degree Celsius.
Correct Answer: C — The heat required to raise the temperature of 1 kg of the substance by 1 degree Celsius
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Q. The uncertainty in a measurement is defined as: (2022)
A.
The difference between the maximum and minimum values
B.
The average of the measurements
C.
The standard deviation
D.
The range of values
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Solution
Uncertainty is often defined as the range of values within which the true value lies.
Correct Answer: A — The difference between the maximum and minimum values
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Q. The unit of force in the SI system is derived from which of the following? (2023)
A.
Mass and length
B.
Mass, length, and time
C.
Length and time
D.
Mass and time
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Solution
The unit of force (Newton) is derived from mass, length, and time: kg·m/s².
Correct Answer: B — Mass, length, and time
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Q. The unit of work is defined as one joule. What is one joule equivalent to? (2023)
A.
One newton meter
B.
One kilogram meter per second
C.
One watt second
D.
One pascal meter
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Solution
One joule is defined as one newton meter (N·m).
Correct Answer: A — One newton meter
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Q. The viscosity of a fluid is a measure of its: (2022)
A.
Density
B.
Pressure
C.
Resistance to flow
D.
Temperature
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Solution
Viscosity measures a fluid's resistance to flow; higher viscosity means the fluid flows less easily.
Correct Answer: C — Resistance to flow
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Q. Two capacitors of capacitance 2μF and 3μF are connected in series. What is the equivalent capacitance? (2019)
A.
1.2μF
B.
1.5μF
C.
0.86μF
D.
5μF
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Solution
For capacitors in series, 1/C_eq = 1/C1 + 1/C2. Thus, 1/C_eq = 1/2 + 1/3 = 5/6, giving C_eq = 6/5 = 1.2μF.
Correct Answer: C — 0.86μF
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Q. Viruses are classified as: (2020)
A.
Living organisms
B.
Non-living entities
C.
Prokaryotes
D.
Eukaryotes
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Solution
Viruses are considered non-living entities as they cannot carry out metabolic processes independently.
Correct Answer: B — Non-living entities
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Q. What are the roots of the equation 3x² - 12x + 12 = 0? (2019)
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Solution
Dividing the equation by 3 gives x² - 4x + 4 = 0, which factors to (x - 2)² = 0, hence the root is 2.
Correct Answer: B — 4
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Q. What are the roots of the equation x² - 5x + 6 = 0? (2021)
A.
1 and 6
B.
2 and 3
C.
3 and 2
D.
0 and 5
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Solution
The roots can be found using the factorization method: (x - 2)(x - 3) = 0, hence the roots are 2 and 3.
Correct Answer: B — 2 and 3
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Q. What does the term 'enthalpy' refer to? (2020)
A.
Internal energy plus pressure times volume
B.
Heat content of a system at constant pressure
C.
Total energy of a system
D.
Work done by the system
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Solution
Enthalpy refers to the heat content of a system at constant pressure, defined as internal energy plus pressure times volume.
Correct Answer: B — Heat content of a system at constant pressure
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Q. What happens to the capacitance of a capacitor if a dielectric material is introduced between its plates? (2021)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes zero
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Solution
The capacitance increases when a dielectric material is introduced, as it reduces the electric field between the plates.
Correct Answer: A — Increases
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Q. What happens to the current in a circuit if the voltage is increased while the resistance remains constant? (2021)
A.
The current decreases
B.
The current increases
C.
The current remains the same
D.
The current becomes zero
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Solution
According to Ohm's Law, if the voltage (V) increases while resistance (R) remains constant, the current (I) will increase.
Correct Answer: B — The current increases
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Q. What happens to the density of a material when it is compressed? (2019)
A.
It decreases
B.
It increases
C.
It remains the same
D.
It becomes zero
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Solution
Density increases when a material is compressed, as mass remains constant while volume decreases.
Correct Answer: B — It increases
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Q. What happens to the entropy of an isolated system? (2020) 2020
A.
It decreases
B.
It remains constant
C.
It increases
D.
It can either increase or decrease
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Solution
According to the second law of thermodynamics, the entropy of an isolated system always increases over time.
Correct Answer: C — It increases
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Q. What happens to the equilibrium position when a catalyst is added to a reaction at equilibrium? (2023)
A.
Shifts to the right
B.
Shifts to the left
C.
No change
D.
Increases Kc
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Solution
A catalyst speeds up both the forward and reverse reactions equally, thus it does not change the position of equilibrium or the value of Kc.
Correct Answer: C — No change
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Q. What happens to the image distance when the object is moved closer to a concave mirror? (2021)
A.
Increases
B.
Decreases
C.
Remains the same
D.
Becomes negative
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Solution
As the object moves closer to a concave mirror, the image distance increases, and the image becomes larger and more distant.
Correct Answer: A — Increases
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Q. What happens to the magnetic field when the current in a solenoid is reversed? (2023)
A.
It remains the same
B.
It disappears
C.
It reverses direction
D.
It doubles
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Solution
When the current in a solenoid is reversed, the direction of the magnetic field also reverses.
Correct Answer: C — It reverses direction
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Q. What happens to the magnetic field when the distance from a long straight conductor is doubled? (2023)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
The magnetic field around a long straight conductor decreases with distance. Specifically, it is inversely proportional to the distance from the conductor.
Correct Answer: B — It halves
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