Physics - Online Test
Q1. The vertical component of Earth’s magnetic field at a place is
equal to the horizontal component. What is the value of angle of dip at this
place?
Answer : Option B
Explaination / Solution:
Q2. The given electrical network is equivalent to
Answer : Option C
Explaination / Solution:
Q3.
The instantaneous values
of alternating current and voltage in a circuit are
Answer : Option D
Explaination / Solution:
Q4. Let E = Eo sin[106
x -ωt] be the electric field of plane electromagnetic wave, the value of ω is
Answer : Option D
Explaination / Solution:
Q5. Three capacitors are
connected in triangle as shown in the figure. The equivalent capacitance
between the points A and C is
Answer : Option B
Explaination / Solution:
Q6. The work functions for metals A, B and C are 1.92 eV, 2.0 eV and 5.0 eV respectively. The metals which will emit photoelectrons for a radiation of wavelength 4100 Å is/are
Answer : Option B
Explaination / Solution:
Both (A) and (B) emits the electrons, because
its work function is less than 3.02eV.
Q7. A piece of copper and another of germanium are cooled from room temperature to 80 K. The resistance of
Answer : Option D
Explaination / Solution:
Q8. The half-life period of a radioactive element A is same as the mean life time of another radioactive element B. Initially both have the same number of atoms. Then
Answer : Option C
Explaination / Solution:
(T1/2)A
= τB
0.693
/ λA = 1/ λB
λA
= 0.693 λB
λA < λB
B
will decay faster rate than A
Q9. A flat dielectric disc of radius R carries an excess charge on its surface. The surface charge density is σ. The disc rotates about an axis perpendicular toits plane passing through the center with angular velocity ω. Find the magnitude of the torque on the disc if it is placed in a uniform magnetic field whose strength is B which is directed perpendicular to the axis of rotation
Answer : Option D
Explaination / Solution:
Q10. The output of the following circuit is 1 when
the input ABC is
Answer : Option A
Explaination / Solution:
Y
= (A+B)C
For
Y = 1; C must be 1
The
input ABC is 101
Y=
(1 + 0).l = 1
