If the decay constant of a radioactive substance is , then its half-life is

Which one of the following statement is true, if half-life of a radioactive substance is 1 month?

Two nuclei have their mass numbers in the ratio of 1:3. The ratio of their nuclear densities would be

The above is a plot of binding energy per nucleon _­against the nuclear mass correspond to different nuclei. Consider four reactions where is the energy released? In which reaction is positive?

Fe(OH)₃ can be separated from Al(OH)₃ by addition of

Which of the following elements (M) reacts with HNO₃ to form MO₂?

An acidic solution contains Cu²⁺, Pb²⁺ and Zn²⁺. If H₂S_(g) is passed through the solution the precipitate will contain

In all the oxyacids of phosphorus, each phosphorus atom is in sp³ hybrid state, i.e., it is tetrahedrally bonded to neighbouring four atoms. All these acids contain P - OH bonds, the hydrogen atom of which are ionisable imparting acidic nature to the compound. The ous acids (oxidation state of P = +1 or +3) also have P - H bonds in which hydrogens are not ionisable (P and hydrogen have nearly same electronegativity). The presence of P - H group in these acids imparts reducing properties. The structure of the various acids are drawn below (note that the tetrahedral shape of phosphorus is not shown only for convenience of representation).

There is very little difference in acid strength in the series H₃PO₄, H₃PO₃ and H₃PO₂ because

If where r = 1, 2, 3 and = 0 …etc, then, is equal to

If A and B are two non-singular square matrices of the same order, the adjoint of AB is equal to

If I =, J =  and B = , then B equals

If A^′ is the transpose of a square matrix A, then

If = 72, then n is equal to

The determinant is equal to zero if

Equation of the line passing though the point of intersection of the lines x + 2y – 3 = 0 and x
+ y –2 = 0 and also through the point (2, 1) is

For such questions, we should know different formulas to find equation of line.

The locus of the point which moves so that the square of its distance from the point (3, 0) is
equal to 7 is

Locus of a point means path traced by the given point while satisfying the given conditions. For such questions, we should know distance formula.