Q. The half-life of a first-order reaction is independent of the initial concentration of the reactant. What is the expression 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, which shows that it is independent of the initial concentration.
Correct Answer:
A
— t1/2 = 0.693/k
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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
Show solution
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 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 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 quadratic equation x² + 4x + 4 = 0 has how many distinct roots? (2021)
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Solution
The discriminant is 4² - 4*1*4 = 0, indicating one distinct root.
Correct Answer:
B
— 1
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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 resonant frequency of an RLC circuit is given by which formula? (2022)
A.
f = 1/(2π√(LC))
B.
f = 2π√(LC)
C.
f = LC
D.
f = R/(2πL)
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Solution
The resonant frequency f of an RLC circuit is given by f = 1/(2π√(LC)).
Correct Answer:
A
— f = 1/(2π√(LC))
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Q. The roots of the equation x² + 2x + k = 0 are real and distinct if k is: (2020)
A.
< 1
B.
≥ 1
C.
≤ 1
D.
> 1
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Solution
For real and distinct roots, the discriminant must be positive: 2² - 4*1*k > 0, which simplifies to k < 1.
Correct Answer:
A
— < 1
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Q. The roots of the equation x² + 4x + 4 = 0 are: (2020)
A.
-2 and -2
B.
2 and 2
C.
0 and 4
D.
1 and 3
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Solution
The equation can be factored as (x + 2)² = 0, giving the double root x = -2.
Correct Answer:
A
— -2 and -2
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Q. The roots of the equation x² + 4x + k = 0 are 2 and -6. What is the value of k? (2021)
A.
-12
B.
-8
C.
-10
D.
-14
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Solution
Using the product of roots: k = 2 * (-6) = -12. The sum is 2 + (-6) = -4, which matches.
Correct Answer:
B
— -8
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Q. The roots of the equation x² - 8x + k = 0 are 4 and 4. Find k. (2021)
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Solution
Using the product of roots: k = 4 * 4 = 16.
Correct Answer:
A
— 16
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Q. The unit of electric charge in the SI system is: (2022)
A.
Coulomb
B.
Ampere
C.
Volt
D.
Ohm
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Solution
Coulomb (C) is the SI unit of electric charge.
Correct Answer:
A
— Coulomb
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Q. The unit of energy equivalent to 1 Joule is: (2023)
A.
1 kg·m²/s²
B.
1 N·m
C.
Both 1 kg·m²/s² and 1 N·m
D.
None of the above
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Solution
1 Joule is defined as 1 kg·m²/s² and also equals 1 N·m, hence both are correct.
Correct Answer:
C
— Both 1 kg·m²/s² and 1 N·m
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Q. The unit of energy in the CGS system is: (2020)
A.
Joule
B.
Erg
C.
Calorie
D.
Watt
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Solution
In the CGS system, the unit of energy is Erg, where 1 Joule = 10^7 Ergs.
Correct Answer:
B
— Erg
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Q. The unit of energy in the SI system is equivalent to which of the following? (2020)
A.
Joule
B.
Newton-meter
C.
Both A and B
D.
None of the above
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Solution
Energy is measured in Joules, and 1 Joule is defined as 1 Newton-meter, hence both A and B are correct.
Correct Answer:
C
— Both A and B
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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 - 2x - 8 = 0? (2022)
A.
-2 and 4
B.
2 and -4
C.
4 and -2
D.
0 and 8
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Solution
Factoring gives (x - 4)(x + 2) = 0, hence the roots are 4 and -2.
Correct Answer:
C
— 4 and -2
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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 parallel plate capacitor if the distance between the plates is increased? (2020)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
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Solution
The capacitance (C) of a parallel plate capacitor is inversely proportional to the distance (d) between the plates. If d increases, C decreases.
Correct Answer:
B
— It decreases
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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 induced current if the magnetic field is suddenly removed from a coil? (2022)
A.
It continues to flow
B.
It stops immediately
C.
It increases
D.
It decreases gradually
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Solution
If the magnetic field is suddenly removed, the change in magnetic flux becomes zero, leading to an immediate stop in the induced current.
Correct Answer:
B
— It stops immediately
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Q. What happens to the magnetic field lines when a magnet is cut into two pieces? (2021)
A.
They disappear
B.
They become weaker
C.
Each piece becomes a magnet with its own field
D.
They merge into one
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Solution
When a magnet is cut into two pieces, each piece becomes a magnet with its own north and south poles, thus maintaining the magnetic field lines.
Correct Answer:
C
— Each piece becomes a magnet with its own field
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Q. What happens to the magnetic field strength inside a solenoid if the number of turns per unit length is increased? (2023)
A.
It decreases
B.
It increases
C.
It remains the same
D.
It becomes zero
Show solution
Solution
The magnetic field strength inside a solenoid is directly proportional to the number of turns per unit length. Therefore, if the number of turns per unit length is increased, the magnetic field strength also increases.
Correct Answer:
B
— It increases
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Q. What happens to the magnetic field strength inside a solenoid if the number of turns is increased? (2023)
A.
It decreases
B.
It remains the same
C.
It increases
D.
It becomes zero
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Solution
The magnetic field strength inside a solenoid increases with the number of turns, as it is directly proportional to the number of turns per unit length.
Correct Answer:
C
— It 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 current in a wire is reversed? (2023)
A.
It remains the same
B.
It doubles
C.
It reverses direction
D.
It disappears
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Solution
When the current in a wire 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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Q. What happens to the particles in a gas when the temperature increases? (2023)
A.
They move slower
B.
They move faster
C.
They stay the same
D.
They condense
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Solution
As the temperature increases, the kinetic energy of gas particles increases, causing them to move faster.
Correct Answer:
B
— They move faster
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