Assertion: Machine parts are jammed in winter.
Reason: The viscosity of lubricant used in machine parts increase at low temperatures

Q. Assertion: $\overrightarrow{\tau }=\overrightarrow{r}\times \overrightarrow{F}but\overrightarrow{\tau }\ne \overrightarrow{F}\times \overrightarrow{r}.$
Reason: Cross product of a vector is commutative.

Q. Read the assertion and reason carefully to mark the correct option out of the options given below:
Assertion: Short wave bands are used for transmission of radio waves to a large distance.
Reason : Short waves are reflected by ionosphere
(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.
(e)If assertion is false but reason is true.

Q.

Read the assertion and reason carefully to mark the correct option out of the options given below :

(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.

(e) If assertion is false but reason is true.

Assertion: Acetic acid does not undergo haloform reaction.

Reason: Acetic acid has no alpha hydrogens.

Q. Assertion : Amount of cyanocobalamine required daily is 3 mcg
Reason : Its deficiency causes pernicious anaemia

Q. Read the assertion and reason carefully to mark the correct option out of the options given below:

(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 assertion is false but reason is true.
Assertion : EV(M${}^{2+}$/M) value for copper is positive (+0.34V).
Reason : High ionization enthalpy and low heat of hydration energy