Why must a car battery have a very low internal resistance?
Correct answer A. So it can supply a large starting current without a large drop in terminal voltage
Subject / 480 questions
MDCAT ECAT Physics MCQs
Page 12 of MDCAT ECAT Physics multiple-choice questions with answers. Tap an option to check yourself.
Page 12 of 24
- Electromagnetic Induction 30
- Fluid Dynamics 30
- Electrostatics 30
- Electronics 30
- Electromagnetism 30
- Current Electricity 30
- Work and Energy 30
- Waves 30
- Vectors and Equilibrium 30
- Nuclear Physics 30
- Dawn of Modern Physics 30
- Thermodynamics 30
- Rotational and Circular Motion 30
- Atomic Spectra 30
- Alternating Current 30
- Force and Motion 30
Which combination of units is equivalent to one tesla?
Correct answer D. N A⁻¹ m⁻¹
How many gauss are equal to one tesla?
Correct answer A. 10⁴ G
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The weber, the SI unit of magnetic flux, is equivalent to which of the following?
Correct answer D. V s
A rectangular loop measuring 0.20 m by 0.10 m is placed with its plane perpendicular to a uniform magnetic field of 0.50 T. What is the magnetic flux through the loop?
Correct answer D. 1.0 × 10⁻² Wb
What is the magnetic flux through a flat coil whose plane is parallel to a uniform magnetic field?
Correct answer D. Zero
A loop of area 0.050 m² is in a uniform field of 0.40 T. The normal to the loop makes an angle of 60° with the field. What is the flux through the loop?
Correct answer C. 1.0 × 10⁻² Wb
Magnetic flux through a plane area A in a uniform field B is maximum when the angle between B and the vector area is ____.
Correct answer C. 0°
What kind of quantity is magnetic flux?
Correct answer D. A scalar, being the dot product of B and A
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Ohm’s law states that the current in a metallic conductor is directly proportional to the potential difference across it, provided which quantity stays constant?
Correct answer D. Temperature of the conductor
What is the SI unit of resistivity?
Correct answer D. Ω m
A steady current of 0.50 A flows through a lamp for 2.0 minutes. How much charge passes through the lamp?
Correct answer C. 60 C
A wire carries a steady current of 3.2 mA. Take e = 1.6 × 10⁻¹⁹ C. How many electrons pass a given cross-section of the wire each second?
Correct answer A. 2.0 × 10¹⁶
Which of the following is a non-ohmic device?
Correct answer C. A semiconductor diode
A uniform wire of resistance R is stretched so that its length doubles while its volume stays the same. What is its new resistance?
Correct answer B. 4R
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A wire 2.0 m long with cross-sectional area 0.50 mm² has a resistance of 2.2 Ω. What is the resistivity of its material?
Correct answer A. 5.5 × 10⁻⁷ Ω m
The resistivity of a metal wire depends on which of the following?
Correct answer D. The material and its temperature
What is the sign of the temperature coefficient of resistance of a pure semiconductor such as silicon?
Correct answer C. Negative
Why does the resistance of a metal conductor increase when its temperature rises?
Correct answer D. Lattice ions vibrate with larger amplitude, so free electrons collide more often
A coil has a resistance of 10 Ω at 0 °C. Its temperature coefficient of resistance is 4.0 × 10⁻³ K⁻¹. What is its resistance at 50 °C?
Correct answer D. 12 Ω