Three coplanar forces acting on a body keep it in equilibrium. What must be true of these forces?
Correct answer B. Concurrent
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Everyday Science MCQs
Page 164 of Everyday Science multiple-choice questions with answers. Tap an option to check yourself.
Page 164 of 198
Two forces of equal magnitude have a resultant with that same magnitude. What is the angle between them?
Correct answer D. 120°
What is the maximum number of components into which a vector can be resolved?
Correct answer D. Infinite
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What does the expression cos θ î + sin θ ĵ represent?
Correct answer C. The unit vector in the direction at angle θ with the x-axis
What is the maximum number of mutually perpendicular (rectangular) components a vector can have?
Correct answer A. 3
What is another name for the rectangular coordinate system?
Correct answer A. Cartesian coordinate system
In which direction does the unit vector n̂ point?
Correct answer B. Normal to a surface
A vector can be multiplied by a number. What kind of number can it be?
Correct answer D. All of A, B and C
How many angles are needed to specify the direction of a vector in space?
Correct answer B. Three angles
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Which laws does vector addition obey?
Correct answer D. All of the laws in A, B and C
Where does an inductor store energy?
Correct answer A. In its magnetic field
Two identical coaxial circular loops carry equal currents in the same direction. What happens to the currents as the loops move towards each other?
Correct answer D. Each decreases
In a series LCR circuit with applied RMS voltage V and RMS voltages V_R, V_L and V_C across R, L and C, which relation holds?
Correct answer A. V² = V_R² + (V_L − V_C)²
In an a.c. circuit containing only resistance, what is the phase angle between voltage and current?
Correct answer C. Zero
In an AC circuit, for which values of voltage and current does Ohm’s law hold?
Correct answer D. All of the above
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A coil has a resistance of 100 Ω. With a 1000 Hz AC supply, the applied voltage leads the current by 45°. What is the inductance of the coil?
Correct answer A. 16 mH
An a.c. series circuit has a resistance of 4 Ω and an inductive reactance of 3 Ω. What is its impedance?
Correct answer D. 5 Ω
What is the power factor of a series L-C-R circuit at resonance?
Correct answer C. 1
In which kind of circuit is a choke used to limit current?
Correct answer B. AC circuits
A 10 Ω electric heater is connected to a 220 V, 50 Hz mains supply. What is the peak potential difference across the heater element?
Correct answer B. 220√2 V