Download App

Current Electricity — Physics STD 12 Science — Question

Rajasthan BoardEnglish MediumSTD 12 SciencePhysicsCurrent Electricity3 Marks
Question
  1. The potential difference applied across a given resistor is altered so that the heat produced per second increases by a factor of 9. By what factor does the applied potential difference change?
  2. In the figure shown, an ammeter A and a resistor of $4\Omega$ are connected to the terminals of the source. The emf of the source is 12 V having an internal resistance of $2\Omega$. Calculate the voltmeter and ammeter readings.
✓

Answer

  1. $H=\frac{V^2}{R}$
$\therefore$ V increases by a factor of  $\sqrt{9}=3$
  1. Ammeter Reading $I=\frac{V}{R+r}$
$=\frac{12}{4+2}A=2A$
Voltmeter Reading $V=E-Ir$
$=[12-(2\times2)]\text{ }\text{V}=8\text{V}$

Need a full question paper?

Generate a complete, print-ready paper with questions like this in minutes — across 16+ boards, with answer keys.

Start Generating Free

Explore more

More "3 Marks Question" from Current Electricity→Current Electricity — all question types→Physics STD 12 Science question papers→Rajasthan Board STD 12 Science question papers→Rajasthan Board question paper generator→

Similar questions

Figure shows a $11.7ft$ wide ditch with the approach roads at an angle of $15^\circ$ with the horizontal. With what minimum speed should a motorbike be moving on the road so that it safely crosses the ditch?
Assume that the length of the bike is $5ft$, and it leaves the road when the front part runs out of the approach road.
→
It is said that any charge given to a conductor comes to its surface. Should all the protons come to the surface? Should all the electrons come to the surface? Should all the free electrons come to the surface?
→
A block of mass $250g$ is kept on a vertical spring of spring constant $100N/m$ fixed from below. The spring is now compressed to have a length $10\ cm$ shorter than its natural length and the system is released from this position. How high does the block rise? Take $g =10m/s^2.$
→
What is the magnitude of magnetic force per unit length on a wire carrying of 8 A and making an angle of 30° with the direction of a uniform magnetic field of 0.15 Т?
→
A neutron is absorbed by a $^{6}_{3}\text{Li}$ nucleus with the subsequent emission of an alpha particle.
  1. Calculate the energy released, in $MeV,$ in this reaction.
  2. Write the corresponding nuclear reaction.
Given: mass $^{6}_{3}\text{Li} =6015126  u;$ mass $($neutron$) =1.0086654 u;$ mass $($alpha particle$) = 4.0026044 u$ and mass $($triton$) = 3.0100000 u.$
Take $1 u = 931\ MeV/C^2.$
→
In a soccer practice session the football is kept at the centre of the field $40$ yards from the $10ft$ high goalposts. A goal is attempted by kicking the football at a speed of $64ft/s$ at an angle of $45^\circ$ to the horizontal. Will the ball reach the goal post?
→
Would the Bohr formula for the $H-$ atom remain unchanged if proton had a charge $(+4/3)e$ and electron a charge $(-3/4)e$, where $e = 1.6 \times 10^{-19}C$. Give reasons for your answer?
→
Explain, with the help of a nuclear reaction in each of the following cases, how the neutron to proton ratio changes during (i) alpha-decay (ii) beta-decay?
→
What is Rydberg constant ? Write down its unit.
→
A spherical conductor of radius $12 \ cm$ has a charge of $1.6 \times 10–7C$ distributed uniformly on its surface. What is the electric field:
  1. Inside the sphere
  2. Just outside the sphere
  3. At a point $18 \ cm$ from the centre of the sphere?
→