Three bodies A, B and C have equal kinetic energies and their masses are 400g,1.2kg and 1.6kg respectively. The ratio of their linear momenta is :
Physicswork-power-and-energy2024easy
A body of mass 50kg is lifted to a height of 20m from the ground in the two different ways as shown in the figures. The ratio of work done against the gravity in both the respective cases, will be :
Physicswork-power-and-energy2024medium
A body is moving unidirectionally under the influence of a constant power source. Its displacement in time t is proportional to :
Physicswork-power-and-energy2024easy
When kinetic energy of a body becomes 36 times of its original value, the percentage increase in the momentum of the body will be :
Physicswork-power-and-energy2024easy
A bullet of mass 50g is fired with a speed 100m/s on a plywood and emerges with 40m/s. The percentage loss of kinetic energy is :
Physicswork-power-and-energy2024easy
Four particles A,B,C,D of mass 2m,m,2m,4m, have same momentum, respectively. The particle with maximum kinetic energy is :
Physicsalternating-current2024easy
A parallel plate capacitor has a capacitance C=200pF. It is connected to 230V ac supply with an angular frequency 300rad/s. The rms value of conduction current in the circuit and displacement current in the capacitor respectively are :
Physicsalternating-current2024easy
In series LCR circuit, the capacitance is changed from $C$ to $4 C$. To keep the resonance frequency unchanged, the new inductance should be:
Physicsalternating-current2024easy
Primary side of a transformer is connected to 230V,50Hz supply. Turns ratio of primary to secondary winding is 10:1. Load resistance connected to secondary side is 46Ω. The power consumed in it is :
Physicsalternating-current2024easy
An AC voltage V=20sin200πt is applied to a series LCR circuit which drives a current I=10sin(200πt+3π). The average power dissipated is:
Physicsalternating-current2024easy
A capacitor of capacitance 100μF is charged to a potential of 12V and connected to a 6.4mH inductor to produce oscillations. The maximum current in the circuit would be :
Physicsalternating-current2024easy
In an a.c. circuit, voltage and current are given by:
V=100sin(100t)V and
I=100sin(100t+3π)mA respectively.
The average power dissipated in one cycle is:
Physicsalternating-current2024medium
An alternating voltage V(t)=220sin100πt volt is applied to a purely resistive load of 50Ω. The time taken for the current to rise from half of the peak value to the peak value is:
Physicsalternating-current2024easy
Primary coil of a transformer is connected to 220V ac. Primary and secondary turns of the transforms are 100 and 10 respectively. Secondary coil of transformer is connected to two series resistances shown in figure. The output voltage (V0) is :
Physicsalternating-current2024medium
A series L.R circuit connected with an ac source E=(25sin1000t)V has a power factor of 21. If the source of emf is changed to E=(20sin2000t)V, the new power factor of the circuit will be :
Physicsalternating-current2024easy
A bulb and a capacitor are connected in series across an ac supply. A dielectric is then placed between the plates of the capacitor. The glow of the bulb :
Physicsalternating-current2024medium
In an ac circuit, the instantaneous current is zero, when the instantaneous voltage is maximum. In this case, the source may be connected to :
A. pure inductor.
B. pure capacitor.
C. pure resistor.
D. combination of an inductor and capacitor.
Choose the correct answer from the options given below :
Physicsalternating-current2024medium
Match List I with List II
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LIST I
LIST II
A.
Purely capacitive circuit
I.
B.
Purely inductive circuit
II.
C.
LCR series at resonance
III.
D.
LCR series circuit
IV.
Choose the correct answer from the options given below:
Physicsalternating-current2024medium
A coil of negligible resistance is connected in series with 90Ω resistor across 120V,60Hz supply. A voltmeter reads 36V across resistance. Inductance of the coil is :
Physicsalternating-current2024easy
A LCR circuit is at resonance for a capacitor C, inductance L and resistance R. Now the value of resistance is halved keeping all other parameters same. The current amplitude at resonance will be now: