1.
A body of mass 5 kg moves with velocity 4 m/s. Enter its momentum in kg·m/s.
#Numerical answer type
Answer and explanation
Answer: 20
Momentum kg·m/s.
ObjectiveMcq
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A body of mass 5 kg moves with velocity 4 m/s. Enter its momentum in kg·m/s.
Momentum kg·m/s.
Which of the following are vector quantities?
Velocity
Speed
Force
Temperature
Velocity and force are vector quantities (have both magnitude and direction). Speed and temperature are scalar quantities.
In a P-N junction diode, which condition allows current to flow easily?
Reverse bias
Zero bias
Forward bias
Both forward and reverse bias
In forward bias, the external voltage reduces the potential barrier, allowing significant current to flow through the diode.
Two resistors of 4 Ω and 6 Ω are connected in parallel across a 12 V supply. What is the total current drawn from the supply?
1.2 A
2 A
5 A
3 A
Current through 4 Ω: A. Current through 6 Ω: A. Total: A.
A projectile is launched at 30° to the horizontal with initial velocity 20 m/s. What is its horizontal range? (g = 10 m/s²)
20 m
40 m
20√3 m
10√3 m
m.
Total internal reflection occurs when light travels from:
Rarer to denser medium at any angle
Denser to rarer medium below critical angle
Denser to rarer medium at or above the critical angle
Rarer to denser medium above critical angle
Total internal reflection occurs when light passes from a denser to a rarer medium at an angle equal to or greater than the critical angle. It is the principle behind optical fibres.
Which property of a magnet is used in an electric motor?
Attraction between like poles
Force on a current-carrying conductor in a magnetic field
Magnetic induction
Self-inductance
Electric motors work on the principle that a current-carrying conductor placed in a magnetic field experiences a force (Fleming's left-hand rule).
What is the approximate speed of sound in air at 0°C?
232 m/s
331 m/s
440 m/s
3 × 10⁸ m/s
The speed of sound in air at 0°C is approximately 331 m/s. It increases with temperature.
Which mode of heat transfer does not require a material medium?
Conduction
Convection
Radiation
Both conduction and convection
Radiation transfers heat through electromagnetic waves and does not need any medium, unlike conduction and convection.
If the radius of the Earth were doubled (mass unchanged), what would happen to the value of g (acceleration due to gravity) at the surface?
g would double
g would remain the same
g would become one-fourth
g would halve
. If R doubles, becomes . So g becomes one-fourth.
An electric bulb draws a current of 0.5 A at 220 V. What is the power consumed by the bulb?
440 W
110 W
55 W
220 W
Power W.
Which type of friction acts on a body that is stationary and has a force applied to it but has not yet started moving?
Kinetic friction
Rolling friction
Static friction
Viscous friction
Static friction acts on a body at rest when an external force is applied but motion has not started. It opposes the tendency of motion.
When a ray of light travels from a denser medium to a rarer medium, it bends:
Towards the normal
Away from the normal
Along the normal
No bending occurs
When light travels from denser to rarer medium, the refracted ray bends away from the normal because speed increases. This follows Snell's law: .