Major Competitive Exams
Q. If the average of five numbers is 30, what is the sum of those numbers? (2023)
A.
120
B.
150
C.
180
D.
200
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Solution
Sum of the numbers = Average × Number of items = 30 × 5 = 150.
Correct Answer: A — 120
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Q. If the average of three consecutive integers is x, what is the value of x? (2023)
A.
x-1
B.
x
C.
x+1
D.
x+2
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Solution
Let the integers be (x-1), x, and (x+1). Their average is (x-1 + x + x+1) / 3 = x.
Correct Answer: B — x
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Q. If the azimuthal quantum number l = 1, what is the shape of the orbital?
A.
Spherical
B.
Dumbbell
C.
Double dumbbell
D.
None of the above
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Solution
The azimuthal quantum number l = 1 corresponds to p orbitals, which have a dumbbell shape.
Correct Answer: B — Dumbbell
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Q. If the balance length of a potentiometer is 50cm for a cell of unknown emf, and the potential gradient is 4 V/m, what is the emf of the cell?
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Solution
The emf is calculated as V = potential gradient × length = 4 V/m × 0.5 m = 2 V.
Correct Answer: B — 4V
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Q. If the balancing length of a potentiometer is found to be 40 cm for a cell of emf 2V, what is the potential gradient if the total length of the wire is 100 cm?
A.
5 V/m
B.
2 V/m
C.
4 V/m
D.
3 V/m
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Solution
The potential gradient is V/L = 2V/0.4m = 5 V/m.
Correct Answer: A — 5 V/m
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Q. If the bar graph illustrates the number of books sold by genre, which genre had the least sales?
A.
Fiction
B.
Non-Fiction
C.
Science
D.
History
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Solution
The bar graph shows that History had the least sales among the listed genres.
Correct Answer: D — History
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Q. If the bar graph indicates a drop in sales for a specific product, what could be a possible reason?
A.
Increased competition
B.
Higher demand
C.
Improved marketing
D.
Seasonal trends
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Solution
A drop in sales could be attributed to increased competition in the market.
Correct Answer: A — Increased competition
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Q. If the bar graph indicates that the sales of Dates increased by 50% from 2021 to 2022, what was the sales figure for 2021 if it was 300 units in 2022? (2021)
A.
150 units
B.
200 units
C.
250 units
D.
300 units
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Solution
If the sales increased by 50%, then the sales figure for 2021 was 200 units.
Correct Answer: B — 200 units
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Q. If the base of a number system is increased by 1, how does the representation of the number '10' change?
A.
It remains the same
B.
It becomes 11
C.
It becomes 1
D.
It becomes 2
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Solution
In base 'b', '10' represents 'b'. In base 'b+1', it becomes '11'.
Correct Answer: B — It becomes 11
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Q. If the Binomial Theorem is applied to (x + 2)^4, what is the term containing x^2?
A.
12x^2
B.
24x^2
C.
36x^2
D.
48x^2
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Solution
The term containing x^2 is C(4,2) * x^2 * 2^2 = 6 * x^2 * 4 = 24x^2.
Correct Answer: B — 24x^2
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Q. If the capacitance in an AC circuit is increased, what happens to the capacitive reactance? (2023)
A.
It increases
B.
It decreases
C.
It remains the same
D.
It becomes zero
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Solution
Capacitive reactance XC = 1/(ωC). If capacitance C increases, XC decreases.
Correct Answer: B — It decreases
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Q. If the capacitance of a capacitor is doubled while keeping the charge constant, what happens to the potential difference across it? (2020)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
Capacitance C is defined as C = Q/V. If C is doubled and Q remains constant, then V must halve to maintain the equation.
Correct Answer: B — It halves
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Q. If the capacitance of a parallel plate capacitor is C, what will be the capacitance if the distance between the plates is doubled? (2020)
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Solution
The capacitance C of a parallel plate capacitor is given by C = εA/d. If the distance d is doubled, the new capacitance will be C/2.
Correct Answer: A — C/2
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Q. If the center of a circle is at (0, 0) and it passes through the point (3, 4), what is the equation of the circle?
A.
x² + y² = 25
B.
x² + y² = 12
C.
x² + y² = 7
D.
x² + y² = 16
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Solution
The radius is 5 (distance from (0,0) to (3,4)), so the equation is x² + y² = 5² = 25.
Correct Answer: A — x² + y² = 25
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Q. If the center of a circle is at (0, 0) and it passes through the point (3, 4), what is the radius of the circle?
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Solution
The radius is the distance from the center to the point, which is √(3² + 4²) = √25 = 5.
Correct Answer: A — 5
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Q. If the charge density of a non-conducting sphere increases linearly with radius, how does the electric field vary inside the sphere?
A.
Linearly with radius
B.
Quadratically with radius
C.
Constant
D.
Inversely with radius
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Solution
The electric field inside a non-conducting sphere with linearly increasing charge density varies linearly with radius.
Correct Answer: A — Linearly with radius
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Q. If the charge density of a non-uniform spherical charge distribution varies as ρ(r) = kr², what is the electric field at the center of the sphere?
A.
0
B.
k/3ε₀
C.
k/4ε₀
D.
k/2ε₀
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Solution
At the center of a non-uniform spherical charge distribution, the electric field is zero due to symmetry.
Correct Answer: A — 0
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Q. If the charge density of a spherical charge distribution increases linearly with radius, how does the electric field vary inside the sphere?
A.
Linearly with radius
B.
Quadratically with radius
C.
Inversely with radius
D.
Constant
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Solution
The electric field inside a non-uniform charge distribution varies quadratically with radius due to the increasing charge density.
Correct Answer: B — Quadratically with radius
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Q. If the charge inside a closed surface is doubled, what happens to the electric flux through the surface?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It becomes zero
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Solution
According to Gauss's law, the electric flux is directly proportional to the enclosed charge, so it doubles.
Correct Answer: A — It doubles
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Q. If the charge on a capacitor is doubled while keeping the voltage constant, what happens to the capacitance? (2022)
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
Capacitance C = Q/V. If Q is doubled and V remains constant, C must also double.
Correct Answer: A — It doubles
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Q. If the charge on a capacitor is doubled while the voltage remains constant, what happens to the capacitance?
A.
It doubles
B.
It halves
C.
It remains the same
D.
It quadruples
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Solution
Capacitance C = Q/V; if Q is doubled and V remains constant, C must halve.
Correct Answer: B — It halves
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Q. If the charge on a capacitor is doubled, what happens to the energy stored in it?
A.
It doubles
B.
It quadruples
C.
It remains the same
D.
It halves
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Solution
The energy stored in a capacitor is given by U = 1/2 * C * V^2. If the charge is doubled, the energy stored quadruples.
Correct Answer: B — It quadruples
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Q. If the charge on a capacitor is doubled, what happens to the energy stored? (2019)
A.
It remains the same
B.
It doubles
C.
It quadruples
D.
It halves
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Solution
The energy stored in a capacitor is proportional to the square of the charge (U = Q^2/(2C)). Doubling the charge increases the energy by a factor of 4.
Correct Answer: C — It quadruples
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Q. If the circumference of a circle is 31.4 cm, what is its radius? (2022)
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
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Solution
Circumference = 2πr; 31.4 = 2 * π * r; r = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is its radius? (Use π = 3.14) (2015)
A.
5 cm
B.
7 cm
C.
10 cm
D.
8 cm
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Solution
Circumference = 2πr, so r = circumference / (2π) = 31.4 / (2 * 3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is the radius of the circle? (Use π = 3.14) (2022)
A.
5 cm
B.
7 cm
C.
10 cm
D.
15 cm
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Solution
Circumference = 2πr. Therefore, r = circumference / (2π) = 31.4 / (2 * 3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is the radius?
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
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Solution
Using the formula C = 2πr, we find r = C/(2π) = 31.4/(2*3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is 31.4 cm, what is the radius? (2020) 2020
A.
5 cm
B.
10 cm
C.
15 cm
D.
20 cm
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Solution
Circumference = 2πr. Therefore, r = Circumference / (2π) = 31.4 cm / (2 * 3.14) = 5 cm.
Correct Answer: A — 5 cm
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Q. If the circumference of a circle is measured as 31.4 cm with an error of 0.2 cm, what is the percentage error?
A.
0.64%
B.
0.5%
C.
1%
D.
0.2%
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Solution
Percentage error = (Absolute error / Measured value) * 100 = (0.2 / 31.4) * 100 ≈ 0.64%.
Correct Answer: A — 0.64%
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Q. If the circumference of a circle is measured as 31.4 cm with an error of 0.2 cm, what is the radius?
A.
5 cm
B.
4.5 cm
C.
5.0 cm
D.
6 cm
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Solution
Circumference = 2πr. Measured circumference = 31.4 cm. Thus, r = 31.4 / (2π) ≈ 5.0 cm.
Correct Answer: C — 5.0 cm
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