If the vibrations of a string are to be increased by a factor of

Previous Year Papers

Download Solved Question Papers Free for Offline Practice and view Solutions Online.

Test Series

Take Zigya Full and Sectional Test Series. Time it out for real assessment and get your results instantly.

Test Yourself

Practice and master your preparation for a specific topic or chapter. Check you scores at the end of the test.
Advertisement

 Multiple Choice QuestionsMultiple Choice Questions

281.

A candidate connects a moving coil ammeter A and a moving coil voltmeter V and a resistance R as shown. If the voltmeter reads 20 V and the ammeter reads 4 A, then R is

  • equal to 5Ω

  • greater than 5Ω

  • less than 5Ω

  • none of these


282.

Two identical galvanometers are taken, one is to be converted into an ammeter and other into a milliammeter. The shunt of milliammeter compared to ammeter is

  • less

  • more

  • zero

  • none of these


Advertisement

283.

If the vibrations of a string are to be increased by a factor of two, the tension in the string should be made

  • twice

  • four times

  • eight times

  • half


B.

four times

The frequency of vibration of a string is given by

n = 12lTm

where l is the length, T the tension and m the mass per unit length.

Given, n1 = n, n2 = 2n

n1n2 = n2n = T1T214 = T1T2

T2 = 4T1

Hence, to increase n by a factor of 2 tension must increase four times.


Advertisement
284.

Which of the following has the minimum resistance?

  • Voltmeter

  • Millivoltmeter

  • Ammeter

  • Milliameter


Advertisement
285.

In a cyclotron, if a deuteron can gain the energy of 40 MeV, then a proton can gain the energy of:

  • 40 MeV

  • 80 MeV

  • 20 MeV

  • 60 MeV


286.

An electron, moving in a uniform magnetic field of induction of intensity B, has its radius directly proportional to:

  • its charge

  • magnetic field

  • speed

  • none of these


287.

A uniform magnetic field is at a right angle to the direction of motion of proton. As a result, the proton describes a circular path of radius 2.5 cm. If the speed of proton is doubled then the radius of the circular path will be :

  • 0.5 cm

  • 2.5 cm

  • 5.0 cm

  • 7.5 cm


288.

An electron accelerated through a potential difference enters into a uniform transverse magnetic field and experience a force F. If the accelerating potential is increased to 2V, the electron in the same magnetic field will experience a force :

  • F

  • F/2

  • 2 F

  • 2F


Advertisement
289.

The certain amount of current when flowing in a properly set tangent galvanometer produces a deflection of 45°. The current be reduced by a factor of ✓3, the deflection would :

  • decrease by 30°

  • decrease by 15°

  • increase by 15°

  • increase by 30°


290.

A wire carrying current I and other carrying 2I in the same direction produce a magnetic field B at the mid-point. What will be the field when 2I wire is switched off?

  • B/2

  • 2B

  • B

  • 4B


Advertisement