List of practice Questions

The half-life of a radioactive substance is $10$ days. This means that
A source and an observer are moving towards each other with a speed equal to $v/2$, where $v$ is the speed of sound. The source is emitting sound of frequency $n$. The frequency heard by one observer will be
1 curie is
To double the covering range of a TV transmitter tower, its height should be made
An alternating voltage V = $V_0 \sin \omega t$ is applied across a circuit. As result $I = I_0 \sin(\omega t - \pi /2)$ flows in it. The power consumed per cycle is
A boy of mass $m$ stands on one end of a wooden planck of length $L$ and mass $M$. The plank is floating on water. If the boy walks from one end of the plank to the other end at a constant speed, the resulting displacement of the plank is given by
Sound waves do not show the phenomenon of
The magnifying power of a compound microscope is high if
: $p$-chlorobenzoic acid is stronger acid than benzoic acid. : Chlorine has electron donating resonance $(+ R )$ effect.
Tasar silkworm feeds on the leaves of
The expression $\frac{\tan A}{1-\cot A} + \frac{\cot A}{1 - \tan A} $ can be written as
Respiratory organs of Cockroach are called-
Companion cells are absent in the phloem of
Histogen theory was put forward by
Phellogen is
Ammonia is converted into urea during ornithine cycle in
Restriction endonucleases are most widely used in recombinant DNA technology. They are obtained from
Water is flowing in streamline motion through a horizontal tube. The pressure at a point in the tube is $p$ where the velocity of flow is $v$. At another point, where the pressure is $p/2$, the velocity of flow is [density of water = $?$]
Interconnected flattened sacs of endoplasmic reticulum are called
In diborane, the number of electrons that account for bonding in the bridges is
In borax the number of $B-O-B$ links and $B-OH$ bonds present are, respectively,
Hypertonic urine formation is characteristic of kidneys of
Haemophilia is an example of
Epidermis is produced from
Which is not a characteristic feature of meristematic cells