In a semiconductor:
A. there are no free electrons at any temperature
B. there are no free electrons at 0 K (zero Kelvin)
C. the number of free electrons is less than that in a conductor
D. the number of free electrons increases with temperature
Choose the correct answer from the options given below:

A body oscillate with SHM according to equation (SI unit),
\( x = 10 \cos(2\pi t + \pi/4) \)
at t= 1.5 s, calculate the speed of the body.

A particle moves three times as fast as an electron. The ratio of the de Broglie wavelength of the particle to that of the electron is \( 1.813 \times 10^{-4} \). The mass of the particle is :

Identify the wrong nuclear equation :

Arrange the following in the increasing order of their energy gap between their conduction and valence bands:
(A) Si
(B) C (diamond)
(C) Ge
(D) Sn
choose the correct answer from the options given below:

A molecule of a substance has a permanent electric dipole moment of magnitude \(10^{-31} C m\).
One mole of this substance is \(100 \%\) polarised by applying a strong electrostatic field of magnitude \(10^8 V m ^{-1}\).
The direction of the field is suddenly changed by an angle of \(60^{\circ}\).
Find the heat released by the substance in aligning its dipoles along the new direction of the field.
(Take 1 mole \(=6 \times 10^{23}\) molecules)

A radioactive nucleus decays as given below:
\( {}_Z^A P \rightarrow {}_{Z+1}^A Q \rightarrow {}_{Z-1}^{A-4} R^* \rightarrow {}_{Z-1}^{A-4} R \)
Which particles are emitted in the sequence?

If 4 individuals in a laboratory population of 40 fruitflies died during a specified time interval, say a week, the death rate in the population during that period is -

Read the passage carefully and answer the given questions.
Recombinant DNA Technology
Asexual reproduction preserves the genetic information, while sexual reproduction permits variation. Traditional hybridization procedures used in plants and animals breeding very often lead to inclusion and multiplication of undesirable genes along with the desired genes. The techniques of genetic engineering, which include creation of recombinant DNA, use of gene cloning and gene transfer, overcome this limitation and allow us to isolate and introduce only one or a set of desirable genes without introducing genes into the target organism.
What is the purpose of using a gene promoter in recombinant DNA technology?

With reference to square matrices, which one of the following statement is NOT correct ?

Select the correct statement/s from the following:
A. Spermatogonia always undergo meiotic cell division.
B. Primary spermatocytes divide by mitotic cell division.
C. Secondary spermatocytes have 23 chromosomes and undergo second meiotic division
D. Spermatozoa are transformed into spermatids.
Choose the correct answer from the options given below:

A long solenoid with 30 turns/cm has a small loop of area \( 3 \text{ cm}^2 \) placed inside it normal to its axis. If the current in the solenoid changes steadily from 3.0 A to 6.0 A in 0.1 s, the induced emf in the loop is :

Observe the given figure and answer the following questions:

Match List - I with List - II.

List I	List ll
(A) Antigen binding site	(I) D
(B) Heavy chain	(II) A
(C) Light chain	(III) B
(D) C-Terminal	(IV) C

Choose the correct answer from the options given below: