Electromagnetic Waves — Physics STD 12 Science — Question

In the circuit shown in the figure, the current through

Assertion  :  NAND or NOR gates are called digital building blocks.
Reason      : The repeated use of NAND (or NOR) gates can produce all the basic or complicated gates.(a) If both assertion and reason are true and the reason is the correct explanation of the assertion.(b) If both assertion and reason are true but reason is not the correct explanation of the assertion.(c) If assertion is true but reason is false.(d) If the assertion and reason both are false.

The energy of emitted photoelectrons depends upon :

A heater coil is cut into two parts of equal length and one of them is used in the heater. The ratio of the heat produced by this half coil to that by the original coil is(a) 2 : 1   (b) 1 : 2(c) 1 : 4    (d) 4 : 1

"The work per unit of charge required to move a charge from a reference point to a specified point, measured in joules per coulomb or volts. The static electric field is the negative of the gradient of the electric potential." comments are given below, select the correct one:

The work done by the external force in bringing the charge q from infinity to a point is called as:

The photoelectric threshold wavelength of a certain metal is 3000Å. If the radiation of 2000Å is incident on the metal(a) Electrons will be emitted(b) Positrons will be emitted(c) Protons will be emitted(d) Electrons will not be emitted

A convex lens is used to form real image of an object on a screen. It is observed that even when the positions of the object and that screen are fixed there are two positions of the lens to form real images.  If the heights of the images are 4 cm and 9 cm respectively, the height of the object is(a) 2.25 cm(b) 6.00 cm(c) 6.50 cm(d) 36.00 cm

Figure shows a conducting loop being pulled out of a magnetic field with a speed u. Which of the four plots shown in figure may represent the power delivered by the pulling agent as a function of the speed u?