81- The orbit of electron moving at rate of 1.6 × 10⁶ m/s in uniform magnetic field of 1.0 × 10⁻³ T. The radius of orbit of electron is: (take mₑ = 9.1 × 10⁻³¹ kg; e = 1.6 × 10⁻¹⁹ C.)
A. 9.1 × 10⁻³ m
B. 9.1 × 10⁻² m
C. 1.9 × 10⁻³ m
D. 1.9 × 10⁻² m
View Answer
Answer : A. 9.1 × 10⁻³ m
Description
82- The moment of inertia of a solid sphere of mass 'm' having radius 'r' about a line passing through its center is:
A. 5/2 mr^2
B. 2/5 mr^2
C. 1/2 mr^2
D. 1/3 mr^2
View Answer
Answer : B. 2/5 mr^2
Description
83- The total energy of a block, executing simple harmonic motion is:
A. Independent of ‘x’
B. Proportional to ‘x’
C. Proportional to ‘x⁻¹’
D. Proportional to ‘x⁻²’
View Answer
Answer : A. Independent of 'x'
Description
84- When an Operational amplifier is used as Inverting amplifier, the angle between its output and input signal is:
A. 30°
B. 45°
C. 90°
D. 180°
View Answer
Answer : D. 180°
Description
85- An air craft of wingspan 50m flies horizontally at an area where the vertical component of the Earth’s magnetic field is 2.0 × 10⁻⁴ T. In order to produce an emf of 1 volt between the aircraft’s wingtips, its speed should be:
A. 100 m/s
B. 1000 m/s
C. 15000 m/s
D. 250000 m/s
View Answer
Answer : A. 100 m/s
Description
86- An astronomical telescope has Magnifying power 5. If the focal length of eyepiece is x cm then what is the focal length of objective?
A. 1m
B. 15cm
C. 25cm
D. 50cm
View Answer
Answer : A. 1m
Description
87- The dimensions of angular velocity (ω) is:
A. MLT⁻¹
B. MLT⁻²
C. M⁰L⁰T⁻¹
D. M⁰L⁰T⁻²
View Answer
Answer : C. M⁰L⁰T⁻¹
Description
88- If 0.3i + 0.5j + dk represents a unit vector, the value of 'd' is:
