Electric Charges and Fields — Physics STD 12 Science — Question

100 cells each of e.m.f. 5 V and internal resistance 1 ohm are to be arranged so as to produce maximum current in a 25 ohms resistance. Each row is to contain equal number of cells. The number of rows should be

(a) 2

(b) 4

(c) 5

(d) 10

An infinite number of charges, each of charge 1 mC, are placed on the x-axis with co-ordinates x = 1, 2, 4, 8, ....¥. If a charge of 1 C is kept at the origin, then what is the net force acting on 1 C charge

(a) 9000 N

(b) 12000 N

(c) 24000 N

(d) 36000 N

According to Maxwell , most of the optical properties of light depend on:

An electron and a proton enter a magnetic field perpendicularly. Both have same kinetic energy. Which of the following is true

(a) Trajectory of electron is less curved	(b) Trajectory of proton is less curved
(c) Both trajectories are equally curved	(d) Both move on straight-line path

Correct relation for triode is

(a)

(b) μ =

(c) μ =

(d) None of these

Find the value of x in the following nuclear reaction.
₇​N¹⁴ + ₂​He⁴ → _x​O¹⁷ + _1​H¹

The shortest wavelength in Balmer’s series for Hydrogen atom is ...A... and this is obtained by substituting ...B ... in Balmer’s formula. Here, A and B refer to?

A moving coil galvanometer has a resistance of 50 Ω and gives full scale deflection for 10 mA. How could it be converted into an ammeter with a full scale deflection for 1A

(a) 50/99 Ω  in series	(b) 50/99 Ω in parallel
(c) 0.01 Ω in series	(d) 0.01 Ω in parallel

A bulb rated at (100W – 200V) is used on a 100V line. The current in the bulb is

(a) amp

(b) 4 amp

(c)  amp

(d) 2 amp

Dual nature of radiation is shown by

(a) Diffraction and reflection	(b) Refraction and diffraction
(c) Photoelectric effect alone	(d) Photoelectric effect and diffraction