Physics - Online Test
Q1. The work function for aluminium surface is 4.2 eV. The cutoff wavelength for the photo electric effect for the surface is
Answer : Option B
Explaination / Solution:
ϕ0=hcλ04.2×1.6×10−19=6.6×10−34×3×108λ0λ0=6.6×10−34×3×1084.2×1.6×10−19=2.946×10−7=2946A∘
Q2. Fourier series of a periodic rectangular wave has a
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. The ceiling of a long hall is 25 m high. What is the maximum horizontal distance that a ball thrown with a speed of 40 m can go without hitting the ceiling of the hall?
Answer : Option B
Explaination / Solution:
Maximum height, h = 25 m
In projectile motion, the maximum height reached by a body projected at an angle θ, is given by the relation:
h =
=> 25 =
= sin2θ = 0.30625
sin θ = 0.5534
∴ θ = sin–1(0.5534) = 33.60°
Horizontal range, R =
=
=
= = 150.5 m
In projectile motion, the maximum height reached by a body projected at an angle θ, is given by the relation:
h =
=> 25 =
= sin2θ = 0.30625
sin θ = 0.5534
∴ θ = sin–1(0.5534) = 33.60°
Horizontal range, R =
=
=
= = 150.5 m
Q4. A hollow spherical conductor of radius 2m carries a charge of 500 μ C. Then electric field strength at its surface is
Answer : Option D
Explaination / Solution:
Q5.
A steel rod 2.0 m long has a cross-sectional area of 0.30 . It is hung by one end from a support, and a 550-kg milling machine is hung from its other end. Determine the resulting strain
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. Two cylinders A and B of equal capacity are connected to each other via a stopcock. A contains a gas at standard temperature and pressure. B is completely evacuated. The entire system is thermally insulated. The stopcock is suddenly opened. What is the final pressure of the gas in A and B?
Answer : Option A
Explaination / Solution:
PV = Pf.2V
Pf = V / 2V
Pf = 0.5P
Q7. According to which model a classical atom is doomed to collapse?
Answer : Option C
Explaination / Solution:
No Explaination.
Q8. The driver of a three-wheeler moving with a speed of 36 km/h sees a child standing in the middle of the road and brings his vehicle to rest in 4.0 s just in time to save the child. The mass of the three-wheeler is 400 kg and the mass of the driver is 65 kg.Find out the deceleration produced and the retarding force on a vehicle.
Answer : Option B
Explaination / Solution:
V= final velocity = 0
V0 = initial velocity = 36 km/h = 10 m/s
F= ma = -465 x 2.5 = -1162.5N (negative sign indicates the retarding force)
Q9. Balram pushes 500kg weight on a horizontal frictionless surface a distance of 10 m. The work done by gravitational force is
Answer : Option C
Explaination / Solution:
angle betwwen force and displacement is
Q10. One example where science predates technology is
Answer : Option B
Explaination / Solution:
The idea of wireless communication predates the discovery of "radio" with experiments in "wireless telegraphy" via inductive and capacitive induction and transmission through the ground, water, and even train tracks from the 1830s on. James Clerk Maxwell showed in theoretical and mathematical form in 1864 that electromagnetic waves could propagate through free space.
Over several years starting in 1894 the Italian inventor Guglielmo Marconi built the first complete, commercially successful wireless telegraphy system
