Physics - Online Test
Q1. The correct equation for a series LCR circuit excited by AC is
Answer : Option A
Explaination / Solution:
The LHS of equation contains expression for current through inductor, resistor and capacitor respectively. Each expression on LHS is a result of basic mathematical derivation. On the rhs we have the overall current in the circuit
Q2. Electric-field magnitude E at points inside and outside a positively charged spherical conductor having charge Q and a radius R are
Answer : Option B
Explaination / Solution:
Electric field inside a spherical conductor is zero since all the charge resides on the surface of the conductor and there is no charge in the interior of the conductor. For all external points, the conductor behaves as though its entire charge is concentrated at its center.
Q3. Flow is said to be steady if
Answer : Option A
Explaination / Solution:
The flow velocity u of a fluid is a vector field
which gives the velocity of an element of fluid at a position x and time t.
The flow of a fluid is said to be steady if u does not vary with time. That is if
Q4. The average kinetic energy of a molecule
Answer : Option A
Explaination / Solution:
E=32kT
E∝T
Q5. For small angles Snell’s law becomes
Answer : Option C
Explaination / Solution:
No Explaination.
Q6. A nucleus of mass number A has a radius R such that
Answer : Option D
Explaination / Solution:
A stable nucleus has approximately constant density. Packing protons and neutrons in the nucleus gives approximately the same total size result as packing hard spheres of a constant size (like marbles) into a tight spherical or almost spherical bag.
Q7. Which of these materials has low coefficient of volume expansion αV ?
Answer : Option A
Explaination / Solution:
Glass is a ceramic material made from silica.So that it has lower coefficient of volume expansion in comparison to metal and liquid.
Q8. what is common to both biot savart law and ampere's law
Answer : Option D
Explaination / Solution:
Both Biot- Savart’s lawand ampere’s circuital lawdeal with the consequences of steady current. Ampere’s circuital law is to Biot- savart’s law as is Gauss’s law to Coulomb’s law in electrostatics.
Q9. Absolute error of the measurement is
Answer : Option B
Explaination / Solution:
Absolute error is defined as the magnitude of difference between the actual and the individual values of any quantity in question.
Say we measure any given quantity for n number of times and a1 , aa2 , aa3 ….. an are the individual values then Arithmetic mean
am =( [a1+a2+a3+ ….. + an]/n )
Now absolute error formula as per definition
Q10. A potential difference of 220 V is maintained across 12000 rheostat. Then voltmeter V has a resistance of 6000 and point C is at one fourth the distance from a to b. Then the reading of voltmeter is
Answer : Option B
Explaination / Solution:
Resistance R = 1/4R = 12000/4 = 3000 parallel. .
This is in series with Rbc.
The current in the circuit I = 220/11000 = 0.02A The reading of the voltmeter is the potential drop across Rp. V = 0.02 * 2000 = 40V
This is in series with Rbc.
The current in the circuit I = 220/11000 = 0.02A The reading of the voltmeter is the potential drop across Rp. V = 0.02 * 2000 = 40V
